diff --git a/aegisub/libaegisub/include/libaegisub/mutex.h b/aegisub/libaegisub/include/libaegisub/mutex.h
index 1e3f854a1..599a58348 100644
--- a/aegisub/libaegisub/include/libaegisub/mutex.h
+++ b/aegisub/libaegisub/include/libaegisub/mutex.h
@@ -102,7 +102,7 @@
 #ifndef GOOGLE_MUTEX_H_
 #define GOOGLE_MUTEX_H_
 
-#include "acconf.h"           // to figure out pthreads support
+#include "config.h"           // to figure out pthreads support
 
 #if defined(NO_THREADS)
   typedef int MutexType;      // to keep a lock-count