diff --git a/libcxx/test/libcxx/transitive_includes.sanitize.py b/libcxx/test/libcxx/transitive_includes.sanitize.py
--- a/libcxx/test/libcxx/transitive_includes.sanitize.py
+++ b/libcxx/test/libcxx/transitive_includes.sanitize.py
@@ -17,11 +17,16 @@
 
 headers = []
 for line in sys.stdin.readlines():
-  match = re.search('c\+\+/v[0-9]+/(.+)', line)
+  # On Windows, the path separators can either be forward slash or backslash.
+  # If it is a backslash, Clang prints it escaped as two consecutive
+  # backslashes, and they need to be escaped in the RE. (Use a raw string for
+  # the pattern to avoid needing another level of escaping on the Python string
+  # literal level.)
+  match = re.search(r'c\+\+(/|\\\\)v[0-9]+(/|\\\\)(.+)', line)
   if not match:
     continue
 
-  header = match.group(1)
+  header = match.group(3)
   if os.path.basename(header).endswith('.h'): # Skip C headers
     continue
 
diff --git a/libcxx/test/libcxx/transitive_includes.sh.cpp b/libcxx/test/libcxx/transitive_includes.sh.cpp
--- a/libcxx/test/libcxx/transitive_includes.sh.cpp
+++ b/libcxx/test/libcxx/transitive_includes.sh.cpp
@@ -31,8 +31,8 @@
 // This test uses --trace-includes, which is not supported by GCC.
 // UNSUPPORTED: gcc
 
-// This test doesn't work on AIX or Windows, but it should. Needs investigation.
-// XFAIL: buildhost=aix, buildhost=windows
+// This test doesn't work on AIX, but it should. Needs investigation.
+// XFAIL: buildhost=aix
 
 // This test is not supported when we remove the transitive includes provided for backwards
 // compatibility. When we bulk-remove them, we'll adjust the includes that are expected by
@@ -70,7 +70,7 @@
     print(f"// {RUN}: {trace_includes} | %{{python}} %S/transitive_includes.sanitize.py > %S/transitive_includes/expected.{normalized_header}")
   else:
     print(f"// {RUN}: {trace_includes} | %{{python}} %S/transitive_includes.sanitize.py > %t.actual.{normalized_header}")
-    print(f"// {RUN}: diff %S/transitive_includes/expected.{normalized_header} %t.actual.{normalized_header}")
+    print(f"// {RUN}: diff -w %S/transitive_includes/expected.{normalized_header} %t.actual.{normalized_header}")
 
   print("#if defined(TEST_{})".format(i))
   print("#include <{}>".format(header))
@@ -82,597 +82,597 @@
 // DO NOT MANUALLY EDIT ANYTHING BETWEEN THE MARKERS BELOW
 // GENERATED-MARKER
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_0 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.algorithm
-// RUN: diff %S/transitive_includes/expected.algorithm %t.actual.algorithm
+// RUN: diff -w %S/transitive_includes/expected.algorithm %t.actual.algorithm
 #if defined(TEST_0)
 #include <algorithm>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_1 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.any
-// RUN: diff %S/transitive_includes/expected.any %t.actual.any
+// RUN: diff -w %S/transitive_includes/expected.any %t.actual.any
 #if defined(TEST_1)
 #include <any>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_2 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.array
-// RUN: diff %S/transitive_includes/expected.array %t.actual.array
+// RUN: diff -w %S/transitive_includes/expected.array %t.actual.array
 #if defined(TEST_2)
 #include <array>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_3 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.atomic
-// RUN: diff %S/transitive_includes/expected.atomic %t.actual.atomic
+// RUN: diff -w %S/transitive_includes/expected.atomic %t.actual.atomic
 #if defined(TEST_3)
 #include <atomic>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_4 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.barrier
-// RUN: diff %S/transitive_includes/expected.barrier %t.actual.barrier
+// RUN: diff -w %S/transitive_includes/expected.barrier %t.actual.barrier
 #if defined(TEST_4)
 #include <barrier>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_5 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.bit
-// RUN: diff %S/transitive_includes/expected.bit %t.actual.bit
+// RUN: diff -w %S/transitive_includes/expected.bit %t.actual.bit
 #if defined(TEST_5)
 #include <bit>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_6 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.bitset
-// RUN: diff %S/transitive_includes/expected.bitset %t.actual.bitset
+// RUN: diff -w %S/transitive_includes/expected.bitset %t.actual.bitset
 #if defined(TEST_6)
 #include <bitset>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_7 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cassert
-// RUN: diff %S/transitive_includes/expected.cassert %t.actual.cassert
+// RUN: diff -w %S/transitive_includes/expected.cassert %t.actual.cassert
 #if defined(TEST_7)
 #include <cassert>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_8 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ccomplex
-// RUN: diff %S/transitive_includes/expected.ccomplex %t.actual.ccomplex
+// RUN: diff -w %S/transitive_includes/expected.ccomplex %t.actual.ccomplex
 #if defined(TEST_8)
 #include <ccomplex>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_9 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cctype
-// RUN: diff %S/transitive_includes/expected.cctype %t.actual.cctype
+// RUN: diff -w %S/transitive_includes/expected.cctype %t.actual.cctype
 #if defined(TEST_9)
 #include <cctype>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_10 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cerrno
-// RUN: diff %S/transitive_includes/expected.cerrno %t.actual.cerrno
+// RUN: diff -w %S/transitive_includes/expected.cerrno %t.actual.cerrno
 #if defined(TEST_10)
 #include <cerrno>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_11 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cfenv
-// RUN: diff %S/transitive_includes/expected.cfenv %t.actual.cfenv
+// RUN: diff -w %S/transitive_includes/expected.cfenv %t.actual.cfenv
 #if defined(TEST_11)
 #include <cfenv>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_12 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cfloat
-// RUN: diff %S/transitive_includes/expected.cfloat %t.actual.cfloat
+// RUN: diff -w %S/transitive_includes/expected.cfloat %t.actual.cfloat
 #if defined(TEST_12)
 #include <cfloat>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_13 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.charconv
-// RUN: diff %S/transitive_includes/expected.charconv %t.actual.charconv
+// RUN: diff -w %S/transitive_includes/expected.charconv %t.actual.charconv
 #if defined(TEST_13)
 #include <charconv>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_14 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.chrono
-// RUN: diff %S/transitive_includes/expected.chrono %t.actual.chrono
+// RUN: diff -w %S/transitive_includes/expected.chrono %t.actual.chrono
 #if defined(TEST_14)
 #include <chrono>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_15 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cinttypes
-// RUN: diff %S/transitive_includes/expected.cinttypes %t.actual.cinttypes
+// RUN: diff -w %S/transitive_includes/expected.cinttypes %t.actual.cinttypes
 #if defined(TEST_15)
 #include <cinttypes>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_16 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ciso646
-// RUN: diff %S/transitive_includes/expected.ciso646 %t.actual.ciso646
+// RUN: diff -w %S/transitive_includes/expected.ciso646 %t.actual.ciso646
 #if defined(TEST_16)
 #include <ciso646>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_17 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.climits
-// RUN: diff %S/transitive_includes/expected.climits %t.actual.climits
+// RUN: diff -w %S/transitive_includes/expected.climits %t.actual.climits
 #if defined(TEST_17)
 #include <climits>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_18 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.clocale
-// RUN: diff %S/transitive_includes/expected.clocale %t.actual.clocale
+// RUN: diff -w %S/transitive_includes/expected.clocale %t.actual.clocale
 #if defined(TEST_18)
 #include <clocale>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_19 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cmath
-// RUN: diff %S/transitive_includes/expected.cmath %t.actual.cmath
+// RUN: diff -w %S/transitive_includes/expected.cmath %t.actual.cmath
 #if defined(TEST_19)
 #include <cmath>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_20 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.codecvt
-// RUN: diff %S/transitive_includes/expected.codecvt %t.actual.codecvt
+// RUN: diff -w %S/transitive_includes/expected.codecvt %t.actual.codecvt
 #if defined(TEST_20)
 #include <codecvt>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_21 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.compare
-// RUN: diff %S/transitive_includes/expected.compare %t.actual.compare
+// RUN: diff -w %S/transitive_includes/expected.compare %t.actual.compare
 #if defined(TEST_21)
 #include <compare>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_22 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.complex
-// RUN: diff %S/transitive_includes/expected.complex %t.actual.complex
+// RUN: diff -w %S/transitive_includes/expected.complex %t.actual.complex
 #if defined(TEST_22)
 #include <complex>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_24 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.concepts
-// RUN: diff %S/transitive_includes/expected.concepts %t.actual.concepts
+// RUN: diff -w %S/transitive_includes/expected.concepts %t.actual.concepts
 #if defined(TEST_24)
 #include <concepts>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_25 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.condition_variable
-// RUN: diff %S/transitive_includes/expected.condition_variable %t.actual.condition_variable
+// RUN: diff -w %S/transitive_includes/expected.condition_variable %t.actual.condition_variable
 #if defined(TEST_25)
 #include <condition_variable>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_26 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.coroutine
-// RUN: diff %S/transitive_includes/expected.coroutine %t.actual.coroutine
+// RUN: diff -w %S/transitive_includes/expected.coroutine %t.actual.coroutine
 #if defined(TEST_26)
 #include <coroutine>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_27 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.csetjmp
-// RUN: diff %S/transitive_includes/expected.csetjmp %t.actual.csetjmp
+// RUN: diff -w %S/transitive_includes/expected.csetjmp %t.actual.csetjmp
 #if defined(TEST_27)
 #include <csetjmp>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_28 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.csignal
-// RUN: diff %S/transitive_includes/expected.csignal %t.actual.csignal
+// RUN: diff -w %S/transitive_includes/expected.csignal %t.actual.csignal
 #if defined(TEST_28)
 #include <csignal>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_29 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cstdarg
-// RUN: diff %S/transitive_includes/expected.cstdarg %t.actual.cstdarg
+// RUN: diff -w %S/transitive_includes/expected.cstdarg %t.actual.cstdarg
 #if defined(TEST_29)
 #include <cstdarg>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_30 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cstdbool
-// RUN: diff %S/transitive_includes/expected.cstdbool %t.actual.cstdbool
+// RUN: diff -w %S/transitive_includes/expected.cstdbool %t.actual.cstdbool
 #if defined(TEST_30)
 #include <cstdbool>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_31 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cstddef
-// RUN: diff %S/transitive_includes/expected.cstddef %t.actual.cstddef
+// RUN: diff -w %S/transitive_includes/expected.cstddef %t.actual.cstddef
 #if defined(TEST_31)
 #include <cstddef>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_32 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cstdint
-// RUN: diff %S/transitive_includes/expected.cstdint %t.actual.cstdint
+// RUN: diff -w %S/transitive_includes/expected.cstdint %t.actual.cstdint
 #if defined(TEST_32)
 #include <cstdint>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_33 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cstdio
-// RUN: diff %S/transitive_includes/expected.cstdio %t.actual.cstdio
+// RUN: diff -w %S/transitive_includes/expected.cstdio %t.actual.cstdio
 #if defined(TEST_33)
 #include <cstdio>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_34 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cstdlib
-// RUN: diff %S/transitive_includes/expected.cstdlib %t.actual.cstdlib
+// RUN: diff -w %S/transitive_includes/expected.cstdlib %t.actual.cstdlib
 #if defined(TEST_34)
 #include <cstdlib>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_35 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cstring
-// RUN: diff %S/transitive_includes/expected.cstring %t.actual.cstring
+// RUN: diff -w %S/transitive_includes/expected.cstring %t.actual.cstring
 #if defined(TEST_35)
 #include <cstring>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_36 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ctgmath
-// RUN: diff %S/transitive_includes/expected.ctgmath %t.actual.ctgmath
+// RUN: diff -w %S/transitive_includes/expected.ctgmath %t.actual.ctgmath
 #if defined(TEST_36)
 #include <ctgmath>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_37 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ctime
-// RUN: diff %S/transitive_includes/expected.ctime %t.actual.ctime
+// RUN: diff -w %S/transitive_includes/expected.ctime %t.actual.ctime
 #if defined(TEST_37)
 #include <ctime>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_39 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cuchar
-// RUN: diff %S/transitive_includes/expected.cuchar %t.actual.cuchar
+// RUN: diff -w %S/transitive_includes/expected.cuchar %t.actual.cuchar
 #if defined(TEST_39)
 #include <cuchar>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_40 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cwchar
-// RUN: diff %S/transitive_includes/expected.cwchar %t.actual.cwchar
+// RUN: diff -w %S/transitive_includes/expected.cwchar %t.actual.cwchar
 #if defined(TEST_40)
 #include <cwchar>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_41 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.cwctype
-// RUN: diff %S/transitive_includes/expected.cwctype %t.actual.cwctype
+// RUN: diff -w %S/transitive_includes/expected.cwctype %t.actual.cwctype
 #if defined(TEST_41)
 #include <cwctype>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_42 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.deque
-// RUN: diff %S/transitive_includes/expected.deque %t.actual.deque
+// RUN: diff -w %S/transitive_includes/expected.deque %t.actual.deque
 #if defined(TEST_42)
 #include <deque>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_44 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.exception
-// RUN: diff %S/transitive_includes/expected.exception %t.actual.exception
+// RUN: diff -w %S/transitive_includes/expected.exception %t.actual.exception
 #if defined(TEST_44)
 #include <exception>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_45 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.execution
-// RUN: diff %S/transitive_includes/expected.execution %t.actual.execution
+// RUN: diff -w %S/transitive_includes/expected.execution %t.actual.execution
 #if defined(TEST_45)
 #include <execution>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_47 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.filesystem
-// RUN: diff %S/transitive_includes/expected.filesystem %t.actual.filesystem
+// RUN: diff -w %S/transitive_includes/expected.filesystem %t.actual.filesystem
 #if defined(TEST_47)
 #include <filesystem>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_49 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.format
-// RUN: diff %S/transitive_includes/expected.format %t.actual.format
+// RUN: diff -w %S/transitive_includes/expected.format %t.actual.format
 #if defined(TEST_49)
 #include <format>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_50 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.forward_list
-// RUN: diff %S/transitive_includes/expected.forward_list %t.actual.forward_list
+// RUN: diff -w %S/transitive_includes/expected.forward_list %t.actual.forward_list
 #if defined(TEST_50)
 #include <forward_list>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_51 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.fstream
-// RUN: diff %S/transitive_includes/expected.fstream %t.actual.fstream
+// RUN: diff -w %S/transitive_includes/expected.fstream %t.actual.fstream
 #if defined(TEST_51)
 #include <fstream>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_52 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.functional
-// RUN: diff %S/transitive_includes/expected.functional %t.actual.functional
+// RUN: diff -w %S/transitive_includes/expected.functional %t.actual.functional
 #if defined(TEST_52)
 #include <functional>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_53 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.future
-// RUN: diff %S/transitive_includes/expected.future %t.actual.future
+// RUN: diff -w %S/transitive_includes/expected.future %t.actual.future
 #if defined(TEST_53)
 #include <future>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_54 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.initializer_list
-// RUN: diff %S/transitive_includes/expected.initializer_list %t.actual.initializer_list
+// RUN: diff -w %S/transitive_includes/expected.initializer_list %t.actual.initializer_list
 #if defined(TEST_54)
 #include <initializer_list>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_56 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.iomanip
-// RUN: diff %S/transitive_includes/expected.iomanip %t.actual.iomanip
+// RUN: diff -w %S/transitive_includes/expected.iomanip %t.actual.iomanip
 #if defined(TEST_56)
 #include <iomanip>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_57 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ios
-// RUN: diff %S/transitive_includes/expected.ios %t.actual.ios
+// RUN: diff -w %S/transitive_includes/expected.ios %t.actual.ios
 #if defined(TEST_57)
 #include <ios>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_58 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.iosfwd
-// RUN: diff %S/transitive_includes/expected.iosfwd %t.actual.iosfwd
+// RUN: diff -w %S/transitive_includes/expected.iosfwd %t.actual.iosfwd
 #if defined(TEST_58)
 #include <iosfwd>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_59 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.iostream
-// RUN: diff %S/transitive_includes/expected.iostream %t.actual.iostream
+// RUN: diff -w %S/transitive_includes/expected.iostream %t.actual.iostream
 #if defined(TEST_59)
 #include <iostream>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_60 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.istream
-// RUN: diff %S/transitive_includes/expected.istream %t.actual.istream
+// RUN: diff -w %S/transitive_includes/expected.istream %t.actual.istream
 #if defined(TEST_60)
 #include <istream>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_61 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.iterator
-// RUN: diff %S/transitive_includes/expected.iterator %t.actual.iterator
+// RUN: diff -w %S/transitive_includes/expected.iterator %t.actual.iterator
 #if defined(TEST_61)
 #include <iterator>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_62 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.latch
-// RUN: diff %S/transitive_includes/expected.latch %t.actual.latch
+// RUN: diff -w %S/transitive_includes/expected.latch %t.actual.latch
 #if defined(TEST_62)
 #include <latch>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_63 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.limits
-// RUN: diff %S/transitive_includes/expected.limits %t.actual.limits
+// RUN: diff -w %S/transitive_includes/expected.limits %t.actual.limits
 #if defined(TEST_63)
 #include <limits>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_65 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.list
-// RUN: diff %S/transitive_includes/expected.list %t.actual.list
+// RUN: diff -w %S/transitive_includes/expected.list %t.actual.list
 #if defined(TEST_65)
 #include <list>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_66 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.locale
-// RUN: diff %S/transitive_includes/expected.locale %t.actual.locale
+// RUN: diff -w %S/transitive_includes/expected.locale %t.actual.locale
 #if defined(TEST_66)
 #include <locale>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_68 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.map
-// RUN: diff %S/transitive_includes/expected.map %t.actual.map
+// RUN: diff -w %S/transitive_includes/expected.map %t.actual.map
 #if defined(TEST_68)
 #include <map>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_70 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.memory
-// RUN: diff %S/transitive_includes/expected.memory %t.actual.memory
+// RUN: diff -w %S/transitive_includes/expected.memory %t.actual.memory
 #if defined(TEST_70)
 #include <memory>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_71 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.mutex
-// RUN: diff %S/transitive_includes/expected.mutex %t.actual.mutex
+// RUN: diff -w %S/transitive_includes/expected.mutex %t.actual.mutex
 #if defined(TEST_71)
 #include <mutex>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_72 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.new
-// RUN: diff %S/transitive_includes/expected.new %t.actual.new
+// RUN: diff -w %S/transitive_includes/expected.new %t.actual.new
 #if defined(TEST_72)
 #include <new>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_73 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.numbers
-// RUN: diff %S/transitive_includes/expected.numbers %t.actual.numbers
+// RUN: diff -w %S/transitive_includes/expected.numbers %t.actual.numbers
 #if defined(TEST_73)
 #include <numbers>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_74 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.numeric
-// RUN: diff %S/transitive_includes/expected.numeric %t.actual.numeric
+// RUN: diff -w %S/transitive_includes/expected.numeric %t.actual.numeric
 #if defined(TEST_74)
 #include <numeric>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_75 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.optional
-// RUN: diff %S/transitive_includes/expected.optional %t.actual.optional
+// RUN: diff -w %S/transitive_includes/expected.optional %t.actual.optional
 #if defined(TEST_75)
 #include <optional>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_76 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ostream
-// RUN: diff %S/transitive_includes/expected.ostream %t.actual.ostream
+// RUN: diff -w %S/transitive_includes/expected.ostream %t.actual.ostream
 #if defined(TEST_76)
 #include <ostream>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_77 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.queue
-// RUN: diff %S/transitive_includes/expected.queue %t.actual.queue
+// RUN: diff -w %S/transitive_includes/expected.queue %t.actual.queue
 #if defined(TEST_77)
 #include <queue>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_78 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.random
-// RUN: diff %S/transitive_includes/expected.random %t.actual.random
+// RUN: diff -w %S/transitive_includes/expected.random %t.actual.random
 #if defined(TEST_78)
 #include <random>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_79 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ranges
-// RUN: diff %S/transitive_includes/expected.ranges %t.actual.ranges
+// RUN: diff -w %S/transitive_includes/expected.ranges %t.actual.ranges
 #if defined(TEST_79)
 #include <ranges>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_80 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ratio
-// RUN: diff %S/transitive_includes/expected.ratio %t.actual.ratio
+// RUN: diff -w %S/transitive_includes/expected.ratio %t.actual.ratio
 #if defined(TEST_80)
 #include <ratio>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_81 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.regex
-// RUN: diff %S/transitive_includes/expected.regex %t.actual.regex
+// RUN: diff -w %S/transitive_includes/expected.regex %t.actual.regex
 #if defined(TEST_81)
 #include <regex>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_82 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.scoped_allocator
-// RUN: diff %S/transitive_includes/expected.scoped_allocator %t.actual.scoped_allocator
+// RUN: diff -w %S/transitive_includes/expected.scoped_allocator %t.actual.scoped_allocator
 #if defined(TEST_82)
 #include <scoped_allocator>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_83 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.semaphore
-// RUN: diff %S/transitive_includes/expected.semaphore %t.actual.semaphore
+// RUN: diff -w %S/transitive_includes/expected.semaphore %t.actual.semaphore
 #if defined(TEST_83)
 #include <semaphore>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_84 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.set
-// RUN: diff %S/transitive_includes/expected.set %t.actual.set
+// RUN: diff -w %S/transitive_includes/expected.set %t.actual.set
 #if defined(TEST_84)
 #include <set>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_86 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.shared_mutex
-// RUN: diff %S/transitive_includes/expected.shared_mutex %t.actual.shared_mutex
+// RUN: diff -w %S/transitive_includes/expected.shared_mutex %t.actual.shared_mutex
 #if defined(TEST_86)
 #include <shared_mutex>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_87 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.span
-// RUN: diff %S/transitive_includes/expected.span %t.actual.span
+// RUN: diff -w %S/transitive_includes/expected.span %t.actual.span
 #if defined(TEST_87)
 #include <span>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_88 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.sstream
-// RUN: diff %S/transitive_includes/expected.sstream %t.actual.sstream
+// RUN: diff -w %S/transitive_includes/expected.sstream %t.actual.sstream
 #if defined(TEST_88)
 #include <sstream>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_89 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.stack
-// RUN: diff %S/transitive_includes/expected.stack %t.actual.stack
+// RUN: diff -w %S/transitive_includes/expected.stack %t.actual.stack
 #if defined(TEST_89)
 #include <stack>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_93 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.stdexcept
-// RUN: diff %S/transitive_includes/expected.stdexcept %t.actual.stdexcept
+// RUN: diff -w %S/transitive_includes/expected.stdexcept %t.actual.stdexcept
 #if defined(TEST_93)
 #include <stdexcept>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_97 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.streambuf
-// RUN: diff %S/transitive_includes/expected.streambuf %t.actual.streambuf
+// RUN: diff -w %S/transitive_includes/expected.streambuf %t.actual.streambuf
 #if defined(TEST_97)
 #include <streambuf>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_98 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.string
-// RUN: diff %S/transitive_includes/expected.string %t.actual.string
+// RUN: diff -w %S/transitive_includes/expected.string %t.actual.string
 #if defined(TEST_98)
 #include <string>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_100 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.string_view
-// RUN: diff %S/transitive_includes/expected.string_view %t.actual.string_view
+// RUN: diff -w %S/transitive_includes/expected.string_view %t.actual.string_view
 #if defined(TEST_100)
 #include <string_view>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_101 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.strstream
-// RUN: diff %S/transitive_includes/expected.strstream %t.actual.strstream
+// RUN: diff -w %S/transitive_includes/expected.strstream %t.actual.strstream
 #if defined(TEST_101)
 #include <strstream>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_102 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.system_error
-// RUN: diff %S/transitive_includes/expected.system_error %t.actual.system_error
+// RUN: diff -w %S/transitive_includes/expected.system_error %t.actual.system_error
 #if defined(TEST_102)
 #include <system_error>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_104 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.thread
-// RUN: diff %S/transitive_includes/expected.thread %t.actual.thread
+// RUN: diff -w %S/transitive_includes/expected.thread %t.actual.thread
 #if defined(TEST_104)
 #include <thread>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_105 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.tuple
-// RUN: diff %S/transitive_includes/expected.tuple %t.actual.tuple
+// RUN: diff -w %S/transitive_includes/expected.tuple %t.actual.tuple
 #if defined(TEST_105)
 #include <tuple>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_106 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.type_traits
-// RUN: diff %S/transitive_includes/expected.type_traits %t.actual.type_traits
+// RUN: diff -w %S/transitive_includes/expected.type_traits %t.actual.type_traits
 #if defined(TEST_106)
 #include <type_traits>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_107 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.typeindex
-// RUN: diff %S/transitive_includes/expected.typeindex %t.actual.typeindex
+// RUN: diff -w %S/transitive_includes/expected.typeindex %t.actual.typeindex
 #if defined(TEST_107)
 #include <typeindex>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_108 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.typeinfo
-// RUN: diff %S/transitive_includes/expected.typeinfo %t.actual.typeinfo
+// RUN: diff -w %S/transitive_includes/expected.typeinfo %t.actual.typeinfo
 #if defined(TEST_108)
 #include <typeinfo>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_110 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.unordered_map
-// RUN: diff %S/transitive_includes/expected.unordered_map %t.actual.unordered_map
+// RUN: diff -w %S/transitive_includes/expected.unordered_map %t.actual.unordered_map
 #if defined(TEST_110)
 #include <unordered_map>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_111 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.unordered_set
-// RUN: diff %S/transitive_includes/expected.unordered_set %t.actual.unordered_set
+// RUN: diff -w %S/transitive_includes/expected.unordered_set %t.actual.unordered_set
 #if defined(TEST_111)
 #include <unordered_set>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_112 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.utility
-// RUN: diff %S/transitive_includes/expected.utility %t.actual.utility
+// RUN: diff -w %S/transitive_includes/expected.utility %t.actual.utility
 #if defined(TEST_112)
 #include <utility>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_113 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.valarray
-// RUN: diff %S/transitive_includes/expected.valarray %t.actual.valarray
+// RUN: diff -w %S/transitive_includes/expected.valarray %t.actual.valarray
 #if defined(TEST_113)
 #include <valarray>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_114 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.variant
-// RUN: diff %S/transitive_includes/expected.variant %t.actual.variant
+// RUN: diff -w %S/transitive_includes/expected.variant %t.actual.variant
 #if defined(TEST_114)
 #include <variant>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_115 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.vector
-// RUN: diff %S/transitive_includes/expected.vector %t.actual.vector
+// RUN: diff -w %S/transitive_includes/expected.vector %t.actual.vector
 #if defined(TEST_115)
 #include <vector>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_116 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.version
-// RUN: diff %S/transitive_includes/expected.version %t.actual.version
+// RUN: diff -w %S/transitive_includes/expected.version %t.actual.version
 #if defined(TEST_116)
 #include <version>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_119 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_algorithm
-// RUN: diff %S/transitive_includes/expected.experimental_algorithm %t.actual.experimental_algorithm
+// RUN: diff -w %S/transitive_includes/expected.experimental_algorithm %t.actual.experimental_algorithm
 #if defined(TEST_119)
 #include <experimental/algorithm>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_120 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_coroutine
-// RUN: diff %S/transitive_includes/expected.experimental_coroutine %t.actual.experimental_coroutine
+// RUN: diff -w %S/transitive_includes/expected.experimental_coroutine %t.actual.experimental_coroutine
 #if defined(TEST_120)
 #include <experimental/coroutine>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_121 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_deque
-// RUN: diff %S/transitive_includes/expected.experimental_deque %t.actual.experimental_deque
+// RUN: diff -w %S/transitive_includes/expected.experimental_deque %t.actual.experimental_deque
 #if defined(TEST_121)
 #include <experimental/deque>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_122 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_forward_list
-// RUN: diff %S/transitive_includes/expected.experimental_forward_list %t.actual.experimental_forward_list
+// RUN: diff -w %S/transitive_includes/expected.experimental_forward_list %t.actual.experimental_forward_list
 #if defined(TEST_122)
 #include <experimental/forward_list>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_123 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_functional
-// RUN: diff %S/transitive_includes/expected.experimental_functional %t.actual.experimental_functional
+// RUN: diff -w %S/transitive_includes/expected.experimental_functional %t.actual.experimental_functional
 #if defined(TEST_123)
 #include <experimental/functional>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_124 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_iterator
-// RUN: diff %S/transitive_includes/expected.experimental_iterator %t.actual.experimental_iterator
+// RUN: diff -w %S/transitive_includes/expected.experimental_iterator %t.actual.experimental_iterator
 #if defined(TEST_124)
 #include <experimental/iterator>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_125 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_list
-// RUN: diff %S/transitive_includes/expected.experimental_list %t.actual.experimental_list
+// RUN: diff -w %S/transitive_includes/expected.experimental_list %t.actual.experimental_list
 #if defined(TEST_125)
 #include <experimental/list>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_126 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_map
-// RUN: diff %S/transitive_includes/expected.experimental_map %t.actual.experimental_map
+// RUN: diff -w %S/transitive_includes/expected.experimental_map %t.actual.experimental_map
 #if defined(TEST_126)
 #include <experimental/map>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_127 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_memory_resource
-// RUN: diff %S/transitive_includes/expected.experimental_memory_resource %t.actual.experimental_memory_resource
+// RUN: diff -w %S/transitive_includes/expected.experimental_memory_resource %t.actual.experimental_memory_resource
 #if defined(TEST_127)
 #include <experimental/memory_resource>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_128 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_propagate_const
-// RUN: diff %S/transitive_includes/expected.experimental_propagate_const %t.actual.experimental_propagate_const
+// RUN: diff -w %S/transitive_includes/expected.experimental_propagate_const %t.actual.experimental_propagate_const
 #if defined(TEST_128)
 #include <experimental/propagate_const>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_129 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_regex
-// RUN: diff %S/transitive_includes/expected.experimental_regex %t.actual.experimental_regex
+// RUN: diff -w %S/transitive_includes/expected.experimental_regex %t.actual.experimental_regex
 #if defined(TEST_129)
 #include <experimental/regex>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_130 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_set
-// RUN: diff %S/transitive_includes/expected.experimental_set %t.actual.experimental_set
+// RUN: diff -w %S/transitive_includes/expected.experimental_set %t.actual.experimental_set
 #if defined(TEST_130)
 #include <experimental/set>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_131 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_simd
-// RUN: diff %S/transitive_includes/expected.experimental_simd %t.actual.experimental_simd
+// RUN: diff -w %S/transitive_includes/expected.experimental_simd %t.actual.experimental_simd
 #if defined(TEST_131)
 #include <experimental/simd>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_132 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_string
-// RUN: diff %S/transitive_includes/expected.experimental_string %t.actual.experimental_string
+// RUN: diff -w %S/transitive_includes/expected.experimental_string %t.actual.experimental_string
 #if defined(TEST_132)
 #include <experimental/string>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_133 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_type_traits
-// RUN: diff %S/transitive_includes/expected.experimental_type_traits %t.actual.experimental_type_traits
+// RUN: diff -w %S/transitive_includes/expected.experimental_type_traits %t.actual.experimental_type_traits
 #if defined(TEST_133)
 #include <experimental/type_traits>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_134 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_unordered_map
-// RUN: diff %S/transitive_includes/expected.experimental_unordered_map %t.actual.experimental_unordered_map
+// RUN: diff -w %S/transitive_includes/expected.experimental_unordered_map %t.actual.experimental_unordered_map
 #if defined(TEST_134)
 #include <experimental/unordered_map>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_135 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_unordered_set
-// RUN: diff %S/transitive_includes/expected.experimental_unordered_set %t.actual.experimental_unordered_set
+// RUN: diff -w %S/transitive_includes/expected.experimental_unordered_set %t.actual.experimental_unordered_set
 #if defined(TEST_135)
 #include <experimental/unordered_set>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_136 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_utility
-// RUN: diff %S/transitive_includes/expected.experimental_utility %t.actual.experimental_utility
+// RUN: diff -w %S/transitive_includes/expected.experimental_utility %t.actual.experimental_utility
 #if defined(TEST_136)
 #include <experimental/utility>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_137 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.experimental_vector
-// RUN: diff %S/transitive_includes/expected.experimental_vector %t.actual.experimental_vector
+// RUN: diff -w %S/transitive_includes/expected.experimental_vector %t.actual.experimental_vector
 #if defined(TEST_137)
 #include <experimental/vector>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_138 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ext_hash_map
-// RUN: diff %S/transitive_includes/expected.ext_hash_map %t.actual.ext_hash_map
+// RUN: diff -w %S/transitive_includes/expected.ext_hash_map %t.actual.ext_hash_map
 #if defined(TEST_138)
 #include <ext/hash_map>
 #endif
 // RUN: %{cxx} %s %{flags} %{compile_flags} --trace-includes -fsyntax-only -DTEST_139 2>&1 | %{python} %S/transitive_includes.sanitize.py > %t.actual.ext_hash_set
-// RUN: diff %S/transitive_includes/expected.ext_hash_set %t.actual.ext_hash_set
+// RUN: diff -w %S/transitive_includes/expected.ext_hash_set %t.actual.ext_hash_set
 #if defined(TEST_139)
 #include <ext/hash_set>
 #endif