[PATCH v2] selftests/mm: include mman header to access MREMAP_DONTUNMAP identifier

[Samasth Norway Ananda]

Definition for MREMAP_DONTUNMAP is not present in glibc older than
2.32 thus throwing an undeclared error when running make on mm. Including
linux/mman.h solves the build error for people having older glibc.

Fixes: 0183d777c29a ("selftests: mm: remove duplicate unneeded defines")
Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
Closes: https://lore.kernel.org/linux-mm/CA+G9fYvV-71XqpCr_jhdDfEtN701fBdG3q+=bafaZiGwUXy_aA@xxxxxxxxxxxxxx/
Tested-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@xxxxxxxxxx>
---
 tools/testing/selftests/mm/mremap_dontunmap.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/mm/mremap_dontunmap.c b/tools/testing/selftests/mm/mremap_dontunmap.c
index ca2359835e75..a06e73ec8568 100644
--- a/tools/testing/selftests/mm/mremap_dontunmap.c
+++ b/tools/testing/selftests/mm/mremap_dontunmap.c
@@ -7,6 +7,7 @@
  */
 #define _GNU_SOURCE
 #include <sys/mman.h>
+#include <linux/mman.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
-- 
2.42.0