[PATCH v4 4/7] selftests/resctrl: Move _GNU_SOURCE define into Makefile

[Ilpo Järvinen]

_GNU_SOURCE is defined in resctrl.h. Defining _GNU_SOURCE has a large
impact on what gets defined when including headers either before or
after it. This can result in compile failures if .c file decides to
include a standard header file before resctrl.h.

It is safer to define _GNU_SOURCE in Makefile so it is always defined
regardless of in which order includes are done.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Tested-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Reviewed-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
 tools/testing/selftests/resctrl/Makefile  | 2 +-
 tools/testing/selftests/resctrl/resctrl.h | 1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/tools/testing/selftests/resctrl/Makefile b/tools/testing/selftests/resctrl/Makefile
index 5073dbc96125..2deac2031de9 100644
--- a/tools/testing/selftests/resctrl/Makefile
+++ b/tools/testing/selftests/resctrl/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
-CFLAGS = -g -Wall -O2 -D_FORTIFY_SOURCE=2
+CFLAGS = -g -Wall -O2 -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE
 CFLAGS += $(KHDR_INCLUDES)
 
 TEST_GEN_PROGS := resctrl_tests
diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
index dd07463cdf48..d9b5df95849d 100644
--- a/tools/testing/selftests/resctrl/resctrl.h
+++ b/tools/testing/selftests/resctrl/resctrl.h
@@ -1,5 +1,4 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#define _GNU_SOURCE
 #ifndef RESCTRL_H
 #define RESCTRL_H
 #include <stdio.h>
-- 
2.30.2