tools/perf/build: Split out feature check: 'libelf-mmap'

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-9fxnxjcmrgbSvipxlwsdQ8fg@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/perf/config/Makefile

@@ -111,6 +111,7 @@ FEATURE_TESTS =				\
 	libelf				\
 	glibc				\
 	dwarf				\
+	libelf-mmap			\
 	libnuma
 
 $(foreach test,$(FEATURE_TESTS),$(call feature_check,$(test),$(test)))
@@ -202,7 +203,7 @@ ifndef NO_LIBELF
   CFLAGS += -DHAVE_LIBELF_SUPPORT
   FLAGS_LIBELF=$(CFLAGS) $(LDFLAGS) $(EXTLIBS)
 
-  ifeq ($(call try-cc,$(SOURCE_ELF_MMAP),$(FLAGS_LIBELF),-DHAVE_LIBELF_MMAP_SUPPORT),y)
+  ifeq ($(feature-libelf-mmap), 1)
     CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
   endif
 
@@ -227,8 +228,7 @@ endif # NO_LIBELF
 
 ifndef NO_LIBELF
   CFLAGS += -DHAVE_LIBELF_SUPPORT
-  FLAGS_LIBELF=$(CFLAGS) $(LDFLAGS) $(EXTLIBS)
-  ifeq ($(call try-cc,$(SOURCE_ELF_MMAP),$(FLAGS_LIBELF),-DHAVE_LIBELF_MMAP_SUPPORT),y)
+  ifeq ($(feature-libelf-mmap), 1)
     CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
   endif # try-cc
 endif # NO_LIBELF

tools/perf/config/feature-checks/Makefile

@@ -9,6 +9,7 @@ FILES=					\
 	test-libelf			\
 	test-glibc			\
 	test-dwarf			\
+	test-libelf-mmap		\
 	test-libnuma
 
 CC := $(CC) -MD
@@ -46,6 +47,9 @@ test-glibc:
 test-dwarf:
 	$(BUILD) -ldw
 
+test-libelf-mmap:
+	$(BUILD) -lelf
+
 test-libnuma:
 	$(BUILD) -lnuma
 

tools/perf/config/feature-checks/test-libelf-mmap.c

@@ -0,0 +1,7 @@
+#include <libelf.h>
+#
+int main(void)
+{
+	Elf *elf = elf_begin(0, ELF_C_READ_MMAP, 0);
+	return (long)elf;
+}