Get prototype from system header.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15220 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/none/tests/linux/mremap4.c b/none/tests/linux/mremap4.c
index 1f83dab..3fe2307 100644
--- a/none/tests/linux/mremap4.c
+++ b/none/tests/linux/mremap4.c
@@ -1,12 +1,11 @@
+#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/stat.h>
-
-
-extern void *mremap(void *, size_t, size_t, int, ...);
+#include <sys/mman.h>
int main()
{
