perf tools: Fix build error due to zfree() cast

It failed to build perf on my ubuntu 10.04 box (gcc 4.4.3):

    CC       util/strlist.o
  cc1: warnings being treated as errors
  util/strlist.c: In function ‘str_node__delete’:
  util/strlist.c:42: error: dereferencing type-punned pointer will break strict-aliasing rules
  util/strlist.c:42: error: dereferencing type-punned pointer will break strict-aliasing rules
    CC       util/strfilter.o
  make: *** [util/strlist.o] Error 1

    CC       util/srcline.o
  cc1: warnings being treated as errors
  util/srcline.c: In function ‘addr2line_init’:
  util/srcline.c:132: error: dereferencing type-punned pointer will break strict-aliasing rules
  util/srcline.c:132: error: dereferencing type-punned pointer will break strict-aliasing rules
  util/srcline.c: In function ‘addr2line_cleanup’:
  util/srcline.c:143: error: dereferencing type-punned pointer will break strict-aliasing rules
  util/srcline.c:143: error: dereferencing type-punned pointer will break strict-aliasing rules
  make: *** [util/srcline.o] Error 1

It seems it only allows to remove 'const' qualifier.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1389276479-9047-1-git-send-email-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/srcline.c

@@ -129,7 +129,7 @@ static struct a2l_data *addr2line_init(const char *path)
 
 out:
 	if (a2l) {
-		zfree((void **)&a2l->input);
+		zfree((char **)&a2l->input);
 		free(a2l);
 	}
 	bfd_close(abfd);
@@ -140,7 +140,7 @@ static void addr2line_cleanup(struct a2l_data *a2l)
 {
 	if (a2l->abfd)
 		bfd_close(a2l->abfd);
-	zfree((void **)&a2l->input);
+	zfree((char **)&a2l->input);
 	zfree(&a2l->syms);
 	free(a2l);
 }

tools/perf/util/strlist.c

@@ -39,7 +39,7 @@ struct rb_node *strlist__node_new(struct rblist *rblist, const void *entry)
 static void str_node__delete(struct str_node *snode, bool dupstr)
 {
 	if (dupstr)
-		zfree((void **)&snode->s);
+		zfree((char **)&snode->s);
 	free(snode);
 }