_GNU_SOURCE is provided by lib.mk, so it should be dropped to prevent
redefinition warnings.

Signed-off-by: Edward Liaw <edliaw@google.com>
---
 tools/testing/selftests/mount/nosymfollow-test.c          | 1 -
 tools/testing/selftests/mount/unprivileged-remount-test.c | 1 -
 2 files changed, 2 deletions(-)

diff --git a/tools/testing/selftests/mount/nosymfollow-test.c b/tools/testing/selftests/mount/nosymfollow-test.c
index 650d6d80a1d2..285453750ffc 100644
--- a/tools/testing/selftests/mount/nosymfollow-test.c
+++ b/tools/testing/selftests/mount/nosymfollow-test.c
@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: GPL-2.0
-#define _GNU_SOURCE
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
diff --git a/tools/testing/selftests/mount/unprivileged-remount-test.c b/tools/testing/selftests/mount/unprivileged-remount-test.c
index d2917054fe3a..daffcf5c2f6d 100644
--- a/tools/testing/selftests/mount/unprivileged-remount-test.c
+++ b/tools/testing/selftests/mount/unprivileged-remount-test.c
@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: GPL-2.0
-#define _GNU_SOURCE
 #include <sched.h>
 #include <stdio.h>
 #include <errno.h>
-- 
2.45.1.288.g0e0cd299f1-goog