diff -u -r ../fish-shell-master/src/fallback.h ./src/fallback.h
--- ../fish-shell-master/src/fallback.h	2015-12-16 10:35:17.000000000 -0500
+++ ./src/fallback.h	2015-12-17 05:05:46.153316539 -0500
@@ -31,7 +31,7 @@
 #if __STDC_VERSION__ < 199901L
 # if __GNUC__ >= 2
 #  define __func__ __FUNCTION__
-# else
+# elif !defined(__func__)
 #  define __func__ "<unknown>"
 # endif
 #endif