diff --git a/compiler-rt/cmake/base-config-ix.cmake b/compiler-rt/cmake/base-config-ix.cmake
--- a/compiler-rt/cmake/base-config-ix.cmake
+++ b/compiler-rt/cmake/base-config-ix.cmake
@@ -228,16 +228,16 @@
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "mips")
       # FIXME: Ideally, we would build the N32 library too.
       if("${COMPILER_RT_MIPS_EL}" AND ("${COMPILER_RT_MIPS32R6}" OR "${COMPILER_RT_MIPS64R6}"))
-        test_target_arch(mipsel "" "-mips32r6" "-mabi=32" "-D_LARGEFILE_SOURCE" "-D_FILE_OFFSET_BITS=64")
+        test_target_arch(mipsel "" "-mips32r6" "-mabi=32" "-D_LARGEFILE_SOURCE=1" "-D_FILE_OFFSET_BITS=64")
         test_target_arch(mips64el "" "-mips64r6" "-mabi=64")
       elseif("${COMPILER_RT_MIPS_EL}")
-        test_target_arch(mipsel "" "-mips32r2" "-mabi=32" "-D_LARGEFILE_SOURCE" "-D_FILE_OFFSET_BITS=64")
+        test_target_arch(mipsel "" "-mips32r2" "-mabi=32" "-D_LARGEFILE_SOURCE=1" "-D_FILE_OFFSET_BITS=64")
         test_target_arch(mips64el "" "-mips64r2" "-mabi=64")
       elseif("${COMPILER_RT_MIPS32R6}" OR "${COMPILER_RT_MIPS64R6}")
-        test_target_arch(mips "" "-mips32r6" "-mabi=32" "-D_LARGEFILE_SOURCE" "-D_FILE_OFFSET_BITS=64")
+        test_target_arch(mips "" "-mips32r6" "-mabi=32" "-D_LARGEFILE_SOURCE=1" "-D_FILE_OFFSET_BITS=64")
         test_target_arch(mips64 "" "-mips64r6" "-mabi=64")
       else()
-        test_target_arch(mips "" "-mips32r2" "-mabi=32" "-D_LARGEFILE_SOURCE" "-D_FILE_OFFSET_BITS=64")
+        test_target_arch(mips "" "-mips32r2" "-mabi=32" "-D_LARGEFILE_SOURCE=1" "-D_FILE_OFFSET_BITS=64")
         test_target_arch(mips64 "" "-mips64r2" "-mabi=64")
       endif()
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "arm")
diff --git a/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt b/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
--- a/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
+++ b/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
@@ -165,7 +165,7 @@
 macro(add_sanitizer_tests_for_arch arch)
   set(extra_flags)
   if( CMAKE_SIZEOF_VOID_P EQUAL 4 )
-    list(APPEND extra_flags "-D_LARGEFILE_SOURCE")
+    list(APPEND extra_flags "-D_LARGEFILE_SOURCE=1")
     list(APPEND extra_flags "-D_FILE_OFFSET_BITS=64")
   endif()
   get_sanitizer_common_lib_for_arch(${arch} SANITIZER_COMMON_LIB)