diff --git a/gcc/alloca.c b/gcc/alloca.c
index 7061cec2d314..12c1122981cb 100644
--- a/gcc/alloca.c
+++ b/gcc/alloca.c
@@ -25,6 +25,13 @@
 #include <config.h>
 #endif
 
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
 #ifdef emacs
 #include "blockinput.h"
 #endif