Index: test/fuzzer/lit.cfg
===================================================================
--- test/fuzzer/lit.cfg
+++ test/fuzzer/lit.cfg
@@ -57,8 +57,7 @@
   if fuzzer_enabled:
     sanitizers.append('fuzzer')
   sanitizers_cmd = ('-fsanitize=%s' % ','.join(sanitizers))
-  isysroot_cmd = ('-isysroot %s' % config.osx_sysroot
-      ) if 'darwin' in config.target_triple else ''
+  isysroot_cmd = config.osx_sysroot_flag if config.osx_sysroot_flag else ''
   include_cmd = '-I%s' % libfuzzer_src_root
   return '%s %s %s -gline-tables-only %s %s %s' % (
       compiler_cmd, std_cmd, link_cmd, isysroot_cmd, sanitizers_cmd, include_cmd)
Index: test/fuzzer/lit.site.cfg.in
===================================================================
--- test/fuzzer/lit.site.cfg.in
+++ test/fuzzer/lit.site.cfg.in
@@ -6,7 +6,7 @@
 config.target_flags = "@LIBFUZZER_TEST_FLAGS@"
 config.c_compiler = "@LIBFUZZER_TEST_COMPILER@"
 
-config.osx_sysroot = "@CMAKE_OSX_SYSROOT@"
+config.osx_sysroot_flag = "@OSX_SYSROOT_FLAG@"
 config.cmake_binary_dir = "@CMAKE_BINARY_DIR@"
 config.target_triple = "@TARGET_TRIPLE@"