perf tools: Improve feature test debuggability

Certain feature tests fail with link errors:

  triton:~/tip/tools/perf/config/feature-checks> make test-libbabeltrace.bin
  gcc -MD  -o test-libbabeltrace.bin test-libbabeltrace.c # -lbabeltrace provided by
  /tmp/cc6dRSqd.o: In function `main':
  test-libbabeltrace.c:(.text+0xf): undefined reference to `bt_ctf_stream_class_get_packet_context_type'

although they should already fail with a build error due to lack of a
proper prototype for the function. Due to this I first tried to find
which library was missing - while it was the whole feature that was
missing from the .h file already.

To solve this, propagate -Wall -Werror to all testcases and remove them
from testcase Makefile rules that used them explicitly.

A missing feature now outputs:

  triton:~/tip/tools/perf/config/feature-checks> make test-libbabeltrace.bin
  gcc -MD  -Wall -Werror -o test-libbabeltrace.bin test-libbabeltrace.c  # -lbabeltrace provided by
  test-libbabeltrace.c: In function ‘main’:
  test-libbabeltrace.c:6:2: error: implicit declaration of function ‘bt_ctf_stream_class_get_packet_context_type’ [-Werror=implicit-function-declaration]

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: David Ahern <david.ahern@oracle.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150228091627.GF31887@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/config/feature-checks/Makefile

@@ -39,24 +39,24 @@ PKG_CONFIG := $(CROSS_COMPILE)pkg-config
 
 all: $(FILES)
 
-BUILD = $(CC) $(CFLAGS) -o $(OUTPUT)$@ $(patsubst %.bin,%.c,$@) $(LDFLAGS)
+BUILD = $(CC) $(CFLAGS) -Wall -Werror -o $(OUTPUT)$@ $(patsubst %.bin,%.c,$@) $(LDFLAGS)
 
 ###############################
 
 test-all.bin:
-	$(BUILD) -Werror -fstack-protector-all -O2 -Werror -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -laudit -I/usr/include/slang -lslang $(shell $(PKG_CONFIG) --libs --cflags gtk+-2.0 2>/dev/null) $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -lbabeltrace
+	$(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -laudit -I/usr/include/slang -lslang $(shell $(PKG_CONFIG) --libs --cflags gtk+-2.0 2>/dev/null) $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -lbabeltrace
 
 test-hello.bin:
 	$(BUILD)
 
 test-pthread-attr-setaffinity-np.bin:
-	$(BUILD) -D_GNU_SOURCE -Werror -lpthread
+	$(BUILD) -D_GNU_SOURCE -lpthread
 
 test-stackprotector-all.bin:
-	$(BUILD) -Werror -fstack-protector-all
+	$(BUILD) -fstack-protector-all
 
 test-fortify-source.bin:
-	$(BUILD) -O2 -Werror -D_FORTIFY_SOURCE=2
+	$(BUILD) -O2 -D_FORTIFY_SOURCE=2
 
 test-bionic.bin:
 	$(BUILD)
@@ -119,10 +119,10 @@ test-libbfd.bin:
 	$(BUILD) -DPACKAGE='"perf"' -lbfd -lz -liberty -ldl
 
 test-liberty.bin:
-	$(CC) -o $(OUTPUT)$@ test-libbfd.c -DPACKAGE='"perf"' -lbfd -ldl -liberty
+	$(CC) -Wall -Werror -o $(OUTPUT)$@ test-libbfd.c -DPACKAGE='"perf"' -lbfd -ldl -liberty
 
 test-liberty-z.bin:
-	$(CC) -o $(OUTPUT)$@ test-libbfd.c -DPACKAGE='"perf"' -lbfd -ldl -liberty -lz
+	$(CC) -Wall -Werror -o $(OUTPUT)$@ test-libbfd.c -DPACKAGE='"perf"' -lbfd -ldl -liberty -lz
 
 test-cplus-demangle.bin:
 	$(BUILD) -liberty
@@ -140,7 +140,7 @@ test-libbabeltrace.bin:
 	$(BUILD) # -lbabeltrace provided by $(FEATURE_CHECK_LDFLAGS-libbabeltrace)
 
 test-sync-compare-and-swap.bin:
-	$(BUILD) -Werror
+	$(BUILD)
 
 test-compile-32.bin:
 	$(CC) -m32 -o $(OUTPUT)$@ test-compile.c