selftests/mm: pass down full CC and CFLAGS to check_config.sh

check_config.sh checks that liburing is available by running the compiler
provided as its first argument.  This makes two assumptions:

1. CC consists of only one word
2. No extra flag is required

Unfortunately, there are many situations where these assumptions don't
hold.  For instance:

- When using Clang, CC consists of multiple words
- When cross-compiling, extra flags may be required to allow the
  compiler to find headers

Remove these assumptions by passing down CC and CFLAGS as-is from the
Makefile, so that the same command line is used as when actually building
the tests.

Link: https://lkml.kernel.org/r/20260122170224.4056513-4-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Usama Anjum <Usama.Anjum@arm.com>
Cc: wang lian <lianux.mm@gmail.com>
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/selftests/mm/Makefile

@@ -230,7 +230,7 @@ $(OUTPUT)/migration: LDLIBS += -lnuma
 $(OUTPUT)/rmap: LDLIBS += -lnuma
 
 local_config.mk local_config.h: check_config.sh
-	/bin/sh ./check_config.sh $(CC)
+	CC="$(CC)" CFLAGS="$(CFLAGS)" ./check_config.sh
 
 EXTRA_CLEAN += local_config.mk local_config.h
 

tools/testing/selftests/mm/check_config.sh

@@ -16,8 +16,7 @@ echo "#include <sys/types.h>"        > $tmpfile_c
 echo "#include <liburing.h>"        >> $tmpfile_c
 echo "int func(void) { return 0; }" >> $tmpfile_c
 
-CC=${1:?"Usage: $0 <compiler> # example compiler: gcc"}
-$CC -c $tmpfile_c -o $tmpfile_o >/dev/null 2>&1
+$CC $CFLAGS -c $tmpfile_c -o $tmpfile_o
 
 if [ -f $tmpfile_o ]; then
     echo "#define LOCAL_CONFIG_HAVE_LIBURING 1"  > $OUTPUT_H_FILE