Add libString.

src/libString/s_copy.c

@@ -0,0 +1,19 @@
+#include <u.h>
+#include <libc.h>
+#include "libString.h"
+
+
+/* return a String containing a copy of the passed char array */
+extern String*
+s_copy(char *cp)
+{
+	String *sp;
+	int len;
+
+	len = strlen(cp)+1;
+	sp = s_newalloc(len);
+	setmalloctag(sp, getcallerpc(&cp));
+	strcpy(sp->base, cp);
+	sp->ptr = sp->base + len - 1;		/* point to 0 terminator */
+	return sp;
+}