perf tools: Convert to BACKTRACE_SUPPORT

For building perf without stack backtrace debug, we can set
NO_BACKTRACE=1 as a argument of make.  It then defines NO_BACKTRACE
macro for C code to do the proper handling.  However it usually used in
a negative semantics - e.g. #ifndef - so we saw double negations which
can be misleading.  Convert it to a positive form to make it more
readable and add _SUPPORT suffix for consistency.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Irina Tirdea <irina.tirdea@gmail.com>
Cc: Irina Tirdea <irina.tirdea@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1349109171-1942-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 5216ade909d0..f9126f89efef 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -45,6 +45,8 @@ include config/utilities.mak
 #
 # Define NO_LIBUNWIND if you do not want libunwind dependency for dwarf
 # backtrace post unwind.
+#
+# Define NO_BACKTRACE if you do not want stack backtrace debug feature
 
 $(OUTPUT)PERF-VERSION-FILE: .FORCE-PERF-VERSION-FILE
         @$(SHELL_PATH) util/PERF-VERSION-GEN $(OUTPUT)
@@ -749,11 +751,9 @@ ifndef NO_STRLCPY
         endif
 endif
 
-ifdef NO_BACKTRACE
-       BASIC_CFLAGS += -DNO_BACKTRACE
-else
-       ifneq ($(call try-cc,$(SOURCE_BACKTRACE),),y)
-               BASIC_CFLAGS += -DNO_BACKTRACE
+ifndef NO_BACKTRACE
+       ifeq ($(call try-cc,$(SOURCE_BACKTRACE),),y)
+               BASIC_CFLAGS += -DBACKTRACE_SUPPORT
        endif
 endif