perf tools: Convert to LIBELF_SUPPORT

For building perf without libelf, we can set NO_LIBELF=1 as a argument
of make.  It then defines NO_LIBELF_SUPPORT 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.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1348824728-14025-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 9cd4913..1df0917 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -503,8 +503,6 @@
 endif
 
 ifdef NO_LIBELF
-BASIC_CFLAGS += -DNO_LIBELF_SUPPORT
-
 EXTLIBS := $(filter-out -lelf,$(EXTLIBS))
 
 # Remove ELF/DWARF dependent codes
@@ -519,9 +517,10 @@
 LIB_OBJS += $(OUTPUT)util/symbol-minimal.o
 
 else # NO_LIBELF
+BASIC_CFLAGS += -DLIBELF_SUPPORT
 
-ifneq ($(call try-cc,$(SOURCE_ELF_MMAP),$(FLAGS_COMMON)),y)
-	BASIC_CFLAGS += -DLIBELF_NO_MMAP
+ifeq ($(call try-cc,$(SOURCE_ELF_MMAP),$(FLAGS_COMMON)),y)
+	BASIC_CFLAGS += -DLIBELF_MMAP
 endif
 
 ifndef NO_DWARF