selftests/mlock2: add missing #define _GNU_SOURCE

On glibc 2.3.6:

    mlock2-tests.c: In function 'seek_to_smaps_entry':
    mlock2-tests.c:158: warning: implicit declaration of function 'getline'

According to the manpage of getline(), it needs _GNU_SOURCE before glibc
2.10.

Signed-off-by: Geert Uytterhoeven <[email protected]>
Acked-by: Eric B Munson <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/tools/testing/selftests/vm/mlock2-tests.c b/tools/testing/selftests/vm/mlock2-tests.c
index 4431994aade2ef6f3b55a67692997d632b8f168e..cb247219f1f7288942d2ce8abd011c51ca452dd1 100644 (file)
--- a/tools/testing/selftests/vm/mlock2-tests.c
+++ b/tools/testing/selftests/vm/mlock2-tests.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include <sys/mman.h>
 #include <stdint.h>
 #include <stdio.h>