diff --git a/libcxx/include/__availability b/libcxx/include/__availability
--- a/libcxx/include/__availability
+++ b/libcxx/include/__availability
@@ -13,7 +13,7 @@
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#   pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 // Libc++ is shipped by various vendors. In particular, it is used as a system
diff --git a/libcxx/include/__bit/byteswap.h b/libcxx/include/__bit/byteswap.h
--- a/libcxx/include/__bit/byteswap.h
+++ b/libcxx/include/__bit/byteswap.h
@@ -16,7 +16,7 @@
 #include <cstdlib>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__filesystem/copy_options.h b/libcxx/include/__filesystem/copy_options.h
--- a/libcxx/include/__filesystem/copy_options.h
+++ b/libcxx/include/__filesystem/copy_options.h
@@ -13,6 +13,10 @@
 #include <__availability>
 #include <__config>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/directory_entry.h b/libcxx/include/__filesystem/directory_entry.h
--- a/libcxx/include/__filesystem/directory_entry.h
+++ b/libcxx/include/__filesystem/directory_entry.h
@@ -26,6 +26,10 @@
 #include <iosfwd>
 #include <system_error>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
diff --git a/libcxx/include/__filesystem/directory_iterator.h b/libcxx/include/__filesystem/directory_iterator.h
--- a/libcxx/include/__filesystem/directory_iterator.h
+++ b/libcxx/include/__filesystem/directory_iterator.h
@@ -23,6 +23,10 @@
 #include <cstddef>
 #include <system_error>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/directory_options.h b/libcxx/include/__filesystem/directory_options.h
--- a/libcxx/include/__filesystem/directory_options.h
+++ b/libcxx/include/__filesystem/directory_options.h
@@ -13,6 +13,10 @@
 #include <__availability>
 #include <__config>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/file_status.h b/libcxx/include/__filesystem/file_status.h
--- a/libcxx/include/__filesystem/file_status.h
+++ b/libcxx/include/__filesystem/file_status.h
@@ -15,6 +15,10 @@
 #include <__filesystem/file_type.h>
 #include <__filesystem/perms.h>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/file_time_type.h b/libcxx/include/__filesystem/file_time_type.h
--- a/libcxx/include/__filesystem/file_time_type.h
+++ b/libcxx/include/__filesystem/file_time_type.h
@@ -14,6 +14,10 @@
 #include <__config>
 #include <chrono>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/file_type.h b/libcxx/include/__filesystem/file_type.h
--- a/libcxx/include/__filesystem/file_type.h
+++ b/libcxx/include/__filesystem/file_type.h
@@ -13,6 +13,10 @@
 #include <__availability>
 #include <__config>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/filesystem_error.h b/libcxx/include/__filesystem/filesystem_error.h
--- a/libcxx/include/__filesystem/filesystem_error.h
+++ b/libcxx/include/__filesystem/filesystem_error.h
@@ -19,6 +19,10 @@
 #include <system_error>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/operations.h b/libcxx/include/__filesystem/operations.h
--- a/libcxx/include/__filesystem/operations.h
+++ b/libcxx/include/__filesystem/operations.h
@@ -24,6 +24,10 @@
 #include <cstdint>
 #include <system_error>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/path.h b/libcxx/include/__filesystem/path.h
--- a/libcxx/include/__filesystem/path.h
+++ b/libcxx/include/__filesystem/path.h
@@ -24,6 +24,10 @@
 # include <locale>
 #endif
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/path_iterator.h b/libcxx/include/__filesystem/path_iterator.h
--- a/libcxx/include/__filesystem/path_iterator.h
+++ b/libcxx/include/__filesystem/path_iterator.h
@@ -19,6 +19,10 @@
 #include <string>
 #include <string_view>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/perm_options.h b/libcxx/include/__filesystem/perm_options.h
--- a/libcxx/include/__filesystem/perm_options.h
+++ b/libcxx/include/__filesystem/perm_options.h
@@ -13,6 +13,10 @@
 #include <__availability>
 #include <__config>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/perms.h b/libcxx/include/__filesystem/perms.h
--- a/libcxx/include/__filesystem/perms.h
+++ b/libcxx/include/__filesystem/perms.h
@@ -13,6 +13,10 @@
 #include <__availability>
 #include <__config>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/recursive_directory_iterator.h b/libcxx/include/__filesystem/recursive_directory_iterator.h
--- a/libcxx/include/__filesystem/recursive_directory_iterator.h
+++ b/libcxx/include/__filesystem/recursive_directory_iterator.h
@@ -22,6 +22,10 @@
 #include <cstddef>
 #include <system_error>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/space_info.h b/libcxx/include/__filesystem/space_info.h
--- a/libcxx/include/__filesystem/space_info.h
+++ b/libcxx/include/__filesystem/space_info.h
@@ -14,6 +14,10 @@
 #include <__config>
 #include <cstdint>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__filesystem/u8path.h b/libcxx/include/__filesystem/u8path.h
--- a/libcxx/include/__filesystem/u8path.h
+++ b/libcxx/include/__filesystem/u8path.h
@@ -15,6 +15,10 @@
 #include <__filesystem/path.h>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 #ifndef _LIBCPP_CXX03_LANG
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
diff --git a/libcxx/include/__format/format_to_n_result.h b/libcxx/include/__format/format_to_n_result.h
--- a/libcxx/include/__format/format_to_n_result.h
+++ b/libcxx/include/__format/format_to_n_result.h
@@ -14,7 +14,7 @@
 #include <__iterator/incrementable_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__format/formatter_floating_point.h b/libcxx/include/__format/formatter_floating_point.h
--- a/libcxx/include/__format/formatter_floating_point.h
+++ b/libcxx/include/__format/formatter_floating_point.h
@@ -35,7 +35,7 @@
 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
diff --git a/libcxx/include/__format/formatter_pointer.h b/libcxx/include/__format/formatter_pointer.h
--- a/libcxx/include/__format/formatter_pointer.h
+++ b/libcxx/include/__format/formatter_pointer.h
@@ -24,7 +24,7 @@
 #include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__format/parser_std_format_spec.h b/libcxx/include/__format/parser_std_format_spec.h
--- a/libcxx/include/__format/parser_std_format_spec.h
+++ b/libcxx/include/__format/parser_std_format_spec.h
@@ -24,7 +24,7 @@
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-# pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
diff --git a/libcxx/include/__iterator/indirectly_comparable.h b/libcxx/include/__iterator/indirectly_comparable.h
--- a/libcxx/include/__iterator/indirectly_comparable.h
+++ b/libcxx/include/__iterator/indirectly_comparable.h
@@ -15,6 +15,10 @@
 #include <__iterator/concepts.h>
 #include <__iterator/projected.h>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if !defined(_LIBCPP_HAS_NO_CONCEPTS)
diff --git a/libcxx/include/__memory/voidify.h b/libcxx/include/__memory/voidify.h
--- a/libcxx/include/__memory/voidify.h
+++ b/libcxx/include/__memory/voidify.h
@@ -14,7 +14,7 @@
 #include <__memory/addressof.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/adjacent_difference.h b/libcxx/include/__numeric/adjacent_difference.h
--- a/libcxx/include/__numeric/adjacent_difference.h
+++ b/libcxx/include/__numeric/adjacent_difference.h
@@ -15,7 +15,7 @@
 #include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/exclusive_scan.h b/libcxx/include/__numeric/exclusive_scan.h
--- a/libcxx/include/__numeric/exclusive_scan.h
+++ b/libcxx/include/__numeric/exclusive_scan.h
@@ -15,7 +15,7 @@
 #include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/gcd_lcm.h b/libcxx/include/__numeric/gcd_lcm.h
--- a/libcxx/include/__numeric/gcd_lcm.h
+++ b/libcxx/include/__numeric/gcd_lcm.h
@@ -16,7 +16,7 @@
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
diff --git a/libcxx/include/__numeric/inclusive_scan.h b/libcxx/include/__numeric/inclusive_scan.h
--- a/libcxx/include/__numeric/inclusive_scan.h
+++ b/libcxx/include/__numeric/inclusive_scan.h
@@ -16,7 +16,7 @@
 #include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/iota.h b/libcxx/include/__numeric/iota.h
--- a/libcxx/include/__numeric/iota.h
+++ b/libcxx/include/__numeric/iota.h
@@ -13,7 +13,7 @@
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/midpoint.h b/libcxx/include/__numeric/midpoint.h
--- a/libcxx/include/__numeric/midpoint.h
+++ b/libcxx/include/__numeric/midpoint.h
@@ -15,7 +15,7 @@
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
diff --git a/libcxx/include/__numeric/partial_sum.h b/libcxx/include/__numeric/partial_sum.h
--- a/libcxx/include/__numeric/partial_sum.h
+++ b/libcxx/include/__numeric/partial_sum.h
@@ -15,7 +15,7 @@
 #include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/reduce.h b/libcxx/include/__numeric/reduce.h
--- a/libcxx/include/__numeric/reduce.h
+++ b/libcxx/include/__numeric/reduce.h
@@ -15,7 +15,7 @@
 #include <__iterator/iterator_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/transform_exclusive_scan.h b/libcxx/include/__numeric/transform_exclusive_scan.h
--- a/libcxx/include/__numeric/transform_exclusive_scan.h
+++ b/libcxx/include/__numeric/transform_exclusive_scan.h
@@ -13,7 +13,7 @@
 #include <__config>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/transform_inclusive_scan.h b/libcxx/include/__numeric/transform_inclusive_scan.h
--- a/libcxx/include/__numeric/transform_inclusive_scan.h
+++ b/libcxx/include/__numeric/transform_inclusive_scan.h
@@ -14,7 +14,7 @@
 #include <__iterator/iterator_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/__numeric/transform_reduce.h b/libcxx/include/__numeric/transform_reduce.h
--- a/libcxx/include/__numeric/transform_reduce.h
+++ b/libcxx/include/__numeric/transform_reduce.h
@@ -15,7 +15,7 @@
 #include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/include/locale.h b/libcxx/include/locale.h
--- a/libcxx/include/locale.h
+++ b/libcxx/include/locale.h
@@ -40,7 +40,7 @@
 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#   pragma GCC system_header
+#pragma GCC system_header
 #endif
 
 #include_next <locale.h>
diff --git a/libcxx/test/libcxx/lint/lint_headers.sh.py b/libcxx/test/libcxx/lint/lint_headers.sh.py
--- a/libcxx/test/libcxx/lint/lint_headers.sh.py
+++ b/libcxx/test/libcxx/lint/lint_headers.sh.py
@@ -13,6 +13,8 @@
         path.endswith('.txt') or
         path.endswith('.modulemap') or
         os.path.basename(path) == '__config' or
+        os.path.basename(path) == '__config_site.in' or
+        os.path.basename(path) == '__libcpp_version' or
         os.path.basename(path) == '__locale' or
         not os.path.isfile(path)
     )
@@ -37,6 +39,12 @@
     for fname in all_headers:
         with open(fname, 'r') as f:
             lines = f.readlines()
+
+        if '#pragma GCC system_header\n' not in lines:
+            if pretty(fname) not in ['__undef_macros']:
+                okay = False
+                print('FAILED TO FIND #pragma GCC system_header in libcxx/include/%s!' % pretty(fname))
+
         # Examine each consecutive run of #include directives.
         prevline = None
         for line in lines: