tools/perf/build: Clean up the libunwind logic in config/Makefile

Nest the rules properly. No change in functionality.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-jjlmizjmhockUs04wqnScnkl@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

tools/perf/config/Makefile

@@ -240,19 +240,19 @@ ifneq ($(ARCH),x86)
 endif
 
 ifndef NO_LIBUNWIND
-# for linking with debug library, run like:
-# make DEBUG=1 LIBUNWIND_DIR=/opt/libunwind/
-ifdef LIBUNWIND_DIR
+  # for linking with debug library, run like:
+  # make DEBUG=1 LIBUNWIND_DIR=/opt/libunwind/
+  ifdef LIBUNWIND_DIR
     LIBUNWIND_CFLAGS  := -I$(LIBUNWIND_DIR)/include
     LIBUNWIND_LDFLAGS := -L$(LIBUNWIND_DIR)/lib
-endif
+  endif
 
-FLAGS_UNWIND=$(LIBUNWIND_CFLAGS) $(CFLAGS) $(LIBUNWIND_LDFLAGS) $(LDFLAGS) $(EXTLIBS) $(LIBUNWIND_LIBS)
-ifneq ($(call try-cc,$(SOURCE_LIBUNWIND),$(FLAGS_UNWIND),libunwind),y)
+  FLAGS_UNWIND=$(LIBUNWIND_CFLAGS) $(CFLAGS) $(LIBUNWIND_LDFLAGS) $(LDFLAGS) $(EXTLIBS) $(LIBUNWIND_LIBS)
+  ifneq ($(call try-cc,$(SOURCE_LIBUNWIND),$(FLAGS_UNWIND),libunwind),y)
     msg := $(warning No libunwind found, disabling post unwind support. Please install libunwind-dev[el] >= 0.99);
     NO_LIBUNWIND := 1
-endif # Libunwind support
-endif # NO_LIBUNWIND
+  endif
+endif
 
 ifndef NO_LIBUNWIND
   CFLAGS += -DHAVE_LIBUNWIND_SUPPORT