diff --git a/runtime/GCCLibraries/libc/string.c b/runtime/GCCLibraries/libc/string.c
index a024c3fa87e..bc262a5f4ce 100644
--- a/runtime/GCCLibraries/libc/string.c
+++ b/runtime/GCCLibraries/libc/string.c
@@ -5,6 +5,7 @@
 //===----------------------------------------------------------------------===//
 
 #include <stdlib.h>
+#include <string.h>
 void *malloc(size_t);
 void free(void *);