tools: Adopt memdup() from tools/perf, moving it to tools/lib/string.c

That will contain more string functions with counterparts, sometimes
verbatim copies, in the kernel.

Acked-by: Wang Nan <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/lib/string.c

@@ -0,0 +1,19 @@
+#include <stdlib.h>
+#include <string.h>
+#include <linux/string.h>
+
+/**
+ * memdup - duplicate region of memory
+ *
+ * @src: memory region to duplicate
+ * @len: memory region length
+ */
+void *memdup(const void *src, size_t len)
+{
+	void *p = malloc(len);
+
+	if (p)
+		memcpy(p, src, len);
+
+	return p;
+}