diff --git a/gcc/config/darwin.h b/gcc/config/darwin.h
index 75b688ebf9eee6d1c171788009cda898d8a39243..c175eade887be59060a19224a075ffdce055d9af 100644
--- a/gcc/config/darwin.h
+++ b/gcc/config/darwin.h
@@ -43,6 +43,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define DARWIN_X86 0
 #define DARWIN_PPC 0
 
+#define OBJECT_FORMAT_MACHO 1
+
 /* Suppress g++ attempt to link in the math library automatically. */
 #define MATH_LIBRARY ""