[PATCH] tests/pid_namespace: Add missing sys/mount.h

["T.J. Mercier" <tjmercier@google.com>]

pid_max.c: In function ‘pid_max_cb’:
pid_max.c:42:15: error: implicit declaration of function ‘mount’
                                       [-Wimplicit-function-declaration]
   42 |         ret = mount("", "/", NULL, MS_PRIVATE | MS_REC, 0);
      |               ^~~~~
pid_max.c:42:36: error: ‘MS_PRIVATE’ undeclared (first use in this
                                  function); did you mean ‘MAP_PRIVATE’?
   42 |         ret = mount("", "/", NULL, MS_PRIVATE | MS_REC, 0);
      |                                    ^~~~~~~~~~
      |                                    MAP_PRIVATE
pid_max.c:42:49: error: ‘MS_REC’ undeclared (first use in this function)
   42 |         ret = mount("", "/", NULL, MS_PRIVATE | MS_REC, 0);
      |                                                 ^~~~~~
pid_max.c:48:9: error: implicit declaration of function ‘umount2’; did
               you mean ‘SYS_umount2’? [-Wimplicit-function-declaration]
   48 |         umount2("/proc", MNT_DETACH);
      |         ^~~~~~~
      |         SYS_umount2
pid_max.c:48:26: error: ‘MNT_DETACH’ undeclared (first use in this
                                                               function)
   48 |         umount2("/proc", MNT_DETACH);

Fixes: 615ab43b838b ("tests/pid_namespace: add pid_max tests")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
---
 tools/testing/selftests/pid_namespace/pid_max.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/pid_namespace/pid_max.c b/tools/testing/selftests/pid_namespace/pid_max.c
index 51c414faabb0..96f274f0582b 100644
--- a/tools/testing/selftests/pid_namespace/pid_max.c
+++ b/tools/testing/selftests/pid_namespace/pid_max.c
@@ -10,6 +10,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <syscall.h>
+#include <sys/mount.h>
 #include <sys/wait.h>
 
 #include "../kselftest_harness.h"
-- 
2.49.0.504.g3bcea36a83-goog