diff --git a/desmume/src/libretro-common/rthreads/rthreads.c b/desmume/src/libretro-common/rthreads/rthreads.c
index e94208ed1..c3f03ca09 100644
--- a/desmume/src/libretro-common/rthreads/rthreads.c
+++ b/desmume/src/libretro-common/rthreads/rthreads.c
@@ -25,6 +25,7 @@
 #endif
 
 #include <stdlib.h>
+#include <string.h>
 
 #include <boolean.h>
 #include <rthreads/rthreads.h>