diff --git a/gcc/protoize.c b/gcc/protoize.c
index f79871ee251..8e914af9268 100644
--- a/gcc/protoize.c
+++ b/gcc/protoize.c
@@ -121,6 +121,7 @@ typedef char * const_pointer_type;
 #include <unistd.h>
 #include <signal.h>
 #include <fcntl.h>
+#include <sys/wait.h>
 
 #else /* !defined(POSIX) */