diff -r e18467d67cfd -r c71e05b4dc2e include/SDL_mutex.h
--- a/include/SDL_mutex.h	Fri Feb 10 03:21:39 2006 +0000
+++ b/include/SDL_mutex.h	Fri Feb 10 06:48:43 2006 +0000
@@ -29,6 +29,7 @@
 */
 
 #include "SDL_stdinc.h"
+#include "SDL_error.h"
 
 #include "begin_code.h"
 /* Set up for C function definitions, even when using C++ */