[PATCH v2 1/2] selftests: proc: Fix proc-empty-vm build error on non x86_64

[Punit Agrawal <punit.agrawal@bytedance.com>]

The proc-empty-vm test is implemented for x86_64 and fails to build
for other architectures. Rather then emitting a compiler error it
would be preferable to only build the test on supported architectures.

Mark proc-empty-vm as a test for x86_64 and customise the Makefile to
build it only when building for this target architecture.

Fixes: 5bc73bb3451b ("proc: test how it holds up with mapping'less process")
Signed-off-by: Punit Agrawal <punit.agrawal@bytedance.com>
---
v1 -> v2
* Fixed missing compilation on x86_64

Previous version
* https://lore.kernel.org/all/20221109110621.1791999-1-punit.agrawal@bytedance.com/

tools/testing/selftests/proc/Makefile | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile
index cd95369254c0..743aaa0cdd52 100644
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -1,14 +1,16 @@
 # SPDX-License-Identifier: GPL-2.0-only
+
+# When ARCH not overridden for crosscompiling, lookup machine
+ARCH ?= $(shell uname -m 2>/dev/null || echo not)
+
 CFLAGS += -Wall -O2 -Wno-unused-function
 CFLAGS += -D_GNU_SOURCE
 LDFLAGS += -pthread
 
-TEST_GEN_PROGS :=
 TEST_GEN_PROGS += fd-001-lookup
 TEST_GEN_PROGS += fd-002-posix-eq
 TEST_GEN_PROGS += fd-003-kthread
 TEST_GEN_PROGS += proc-loadavg-001
-TEST_GEN_PROGS += proc-empty-vm
 TEST_GEN_PROGS += proc-pid-vm
 TEST_GEN_PROGS += proc-self-map-files-001
 TEST_GEN_PROGS += proc-self-map-files-002
@@ -26,4 +28,8 @@ TEST_GEN_PROGS += thread-self
 TEST_GEN_PROGS += proc-multiple-procfs
 TEST_GEN_PROGS += proc-fsconfig-hidepid
 
+TEST_GEN_PROGS_x86_64 += proc-empty-vm
+
+TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(ARCH))
+
 include ../lib.mk
-- 
2.35.1