perf util: Replace strerror with strerror_r for thread-safety

Replaces all strerror with strerror_r in util for making the perf lib
thread-safe.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naohiro Aota <naota@elisp.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20140814022236.3545.3367.stgit@kbuild-fedora.novalocal
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index bdafd30..55e39dc 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -162,13 +162,15 @@
 static int do_open(char *name)
 {
 	int fd;
+	char sbuf[STRERR_BUFSIZE];
 
 	do {
 		fd = open(name, O_RDONLY);
 		if (fd >= 0)
 			return fd;
 
-		pr_debug("dso open failed, mmap: %s\n", strerror(errno));
+		pr_debug("dso open failed, mmap: %s\n",
+			 strerror_r(errno, sbuf, sizeof(sbuf)));
 		if (!dso__data_open_cnt || errno != EMFILE)
 			break;
 
@@ -530,10 +532,12 @@
 static int data_file_size(struct dso *dso)
 {
 	struct stat st;
+	char sbuf[STRERR_BUFSIZE];
 
 	if (!dso->data.file_size) {
 		if (fstat(dso->data.fd, &st)) {
-			pr_err("dso mmap failed, fstat: %s\n", strerror(errno));
+			pr_err("dso mmap failed, fstat: %s\n",
+				strerror_r(errno, sbuf, sizeof(sbuf)));
 			return -1;
 		}
 		dso->data.file_size = st.st_size;