[RFC 5/6] perf build: Add feature-dump target

[Jiri Olsa <jolsa@kernel.org>]

To provide FEATURE-DUMP into $(FEATURE_DUMP_COPY)
if defined, with no further action.

Get feature dump of the current build:
  $ make feature-dump
    BUILD:   Doing 'make -j4' parallel build

  Auto-detecting system features:
  ...                         dwarf: [ on  ]

  FEATURE-DUMP file available in FEATURE-DUMP

Get feature dump static build into /tmp/fd file:
  $ make feature-dump FEATURE_DUMP_COPY=/tmp/fd LDFLAGS=-static
    BUILD:   Doing 'make -j4' parallel build

  Auto-detecting system features:
  ...                         dwarf: [ OFF ]

  SNIP

  FEATURE-DUMP file copied into /tmp/fd

Suggested-by: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-xzqhfxw3euqmls3cve0ruuol@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/Makefile.perf | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 0a22407e1d7d..f758a72df1b3 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -611,6 +611,17 @@ clean: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean
 	$(python-clean)
 
 #
+# To provide FEATURE-DUMP into $(FEATURE_DUMP_COPY)
+# file if defined, with no further action.
+feature-dump:
+ifdef FEATURE_DUMP_COPY
+	@cp $(OUTPUT)FEATURE-DUMP $(FEATURE_DUMP_COPY)
+	@echo "FEATURE-DUMP file copied into $(FEATURE_DUMP_COPY)"
+else
+	@echo "FEATURE-DUMP file available in $(OUTPUT)FEATURE-DUMP"
+endif
+
+#
 # Trick: if ../../.git does not exist - we are building out of tree for example,
 # then force version regeneration:
 #
-- 
2.4.3