diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 788460d657fe..812373236ada 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -39,6 +39,9 @@
 #include <mach-o/dyld.h>
 #include <sys/attr.h>
 #include <copyfile.h>
+#ifndef COPYFILE_CLONE
+#define COPYFILE_CLONE	 (1<<24)
+#endif
 #if __has_include(<sys/clonefile.h>)
 #include <sys/clonefile.h>
 #endif
