perf build: Introduce FEATURES_DUMP make variable

Introducing FEATURES_DUMP make variable to provide features
detection dump file and bypass the feature detection.

The intention is to use this during build tests to skip
repeated features detection, like:

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

Use /tmp/fd to build perf:
  $ make FEATURES_DUMP=/tmp/fd LDFLAGS=-static

  $ file perf
  perf: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, for ...

Suggested-by: Wang Nan <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions