perf tools: Add memdup function

Adding memdup function to duplicate region of memory.

  void *memdup(const void *src, size_t len)

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1347295819-23177-3-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/include/linux/string.h

@@ -1 +1,3 @@
 #include <string.h>
+
+void *memdup(const void *src, size_t len);

tools/perf/util/string.c

@@ -1,5 +1,5 @@
 #include "util.h"
-#include "string.h"
+#include "linux/string.h"
 
 #define K 1024LL
 /*
@@ -335,3 +335,19 @@ char *rtrim(char *s)
 
 	return s;
 }
+
+/**
+ * memdup - duplicate region of memory
+ * @src: memory region to duplicate
+ * @len: memory region length
+ */
+void *memdup(const void *src, size_t len)
+{
+	void *p;
+
+	p = malloc(len);
+	if (p)
+		memcpy(p, src, len);
+
+	return p;
+}