Submitted to freebsd-hackers on 2011-07-04

--- a/sys/sys/cdefs.h
+++ b/sys/sys/cdefs.h
@@ -349,7 +349,7 @@
 #endif
 
 /* Compiler-dependent macros that rely on FreeBSD-specific extensions. */
-#if __FreeBSD_cc_version >= 300001 && defined(__GNUC__) && !defined(__INTEL_COMPILER)
+#if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && defined(__GNUC__) && !defined(__INTEL_COMPILER)
 #define	__printf0like(fmtarg, firstvararg) \
 	    __attribute__((__format__ (__printf0__, fmtarg, firstvararg)))
 #else