[PATCH 1/4] perf tools: pass PYTHON config to feature detection

[David Carrillo-Cisneros <davidcc@google.com>]

Python's CC and link Makefile variables were not passed to feature
detection, causing feature detection to use system's Python rather than
PYTHON_CONFIG's one. This created a mismatch between the detected Python
support and the one actually used by perf when PYTHON_CONFIG is specified.

Fix it by moving Python's variable initialization to before feature
detection and pass FLAGS_PYTHON_EMBED to Python's feature detection's
build target.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
---
 tools/build/feature/Makefile |  2 +-
 tools/perf/Makefile.config   | 23 ++++++++++-------------
 2 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index b564a2eea039..3dd2c600d250 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -171,7 +171,7 @@ $(OUTPUT)test-libperl.bin:
 	$(BUILD) $(FLAGS_PERL_EMBED)
 
 $(OUTPUT)test-libpython.bin:
-	$(BUILD)
+	$(BUILD) $(FLAGS_PYTHON_EMBED)
 
 $(OUTPUT)test-libpython-version.bin:
 	$(BUILD)
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 03cf947755b9..41f5c41c5660 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -166,10 +166,18 @@ PYTHON2_CONFIG := \
 override PYTHON_CONFIG := \
   $(call get-executable-or-default,PYTHON_CONFIG,$(PYTHON2_CONFIG))
 
+grep-libs  = $(filter -l%,$(1))
+strip-libs  = $(filter-out -l%,$(1))
+
 PYTHON_CONFIG_SQ := $(call shell-sq,$(PYTHON_CONFIG))
 
-PYTHON_EMBED_LDOPTS := $(shell $(PYTHON_CONFIG_SQ) --ldflags 2>/dev/null)
-PYTHON_EMBED_CCOPTS := $(shell $(PYTHON_CONFIG_SQ) --cflags 2>/dev/null)
+ifdef PYTHON_CONFIG
+  PYTHON_EMBED_LDOPTS := $(shell $(PYTHON_CONFIG_SQ) --ldflags 2>/dev/null)
+  PYTHON_EMBED_LDFLAGS := $(call strip-libs,$(PYTHON_EMBED_LDOPTS))
+  PYTHON_EMBED_LIBADD := $(call grep-libs,$(PYTHON_EMBED_LDOPTS)) -lutil
+  PYTHON_EMBED_CCOPTS := $(shell $(PYTHON_CONFIG_SQ) --cflags 2>/dev/null)
+  FLAGS_PYTHON_EMBED := $(PYTHON_EMBED_CCOPTS) $(PYTHON_EMBED_LDOPTS)
+endif
 
 FEATURE_CHECK_CFLAGS-libpython := $(PYTHON_EMBED_CCOPTS)
 FEATURE_CHECK_LDFLAGS-libpython := $(PYTHON_EMBED_LDOPTS)
@@ -542,8 +550,6 @@ ifndef NO_GTK2
   endif
 endif
 
-grep-libs  = $(filter -l%,$(1))
-strip-libs = $(filter-out -l%,$(1))
 
 ifdef NO_LIBPERL
   CFLAGS += -DNO_LIBPERL
@@ -591,18 +597,9 @@ else
       $(call disable-python,No 'python-config' tool was found: disables Python support - please install python-devel/python-dev)
     else
 
-      PYTHON_CONFIG_SQ := $(call shell-sq,$(PYTHON_CONFIG))
-
-      PYTHON_EMBED_LDOPTS := $(shell $(PYTHON_CONFIG_SQ) --ldflags 2>/dev/null)
-      PYTHON_EMBED_LDFLAGS := $(call strip-libs,$(PYTHON_EMBED_LDOPTS))
-      PYTHON_EMBED_LIBADD := $(call grep-libs,$(PYTHON_EMBED_LDOPTS)) -lutil
-      PYTHON_EMBED_CCOPTS := $(shell $(PYTHON_CONFIG_SQ) --cflags 2>/dev/null)
-      FLAGS_PYTHON_EMBED := $(PYTHON_EMBED_CCOPTS) $(PYTHON_EMBED_LDOPTS)
-
       ifneq ($(feature-libpython), 1)
         $(call disable-python,No 'Python.h' (for Python 2.x support) was found: disables Python support - please install python-devel/python-dev)
       else
-
         ifneq ($(feature-libpython-version), 1)
           $(warning Python 3 is not yet supported; please set)
           $(warning PYTHON and/or PYTHON_CONFIG appropriately.)
-- 
2.11.0.483.g087da7b7c-goog