new utilities.

the .C files compile but are renamed to avoid building automatically.

src/cmd/mkdir.C

@@ -0,0 +1,26 @@
+#include <u.h>
+#include <libc.h>
+
+void
+main(int argc, char *argv[])
+{
+	int i, f;
+	char *e;
+
+	e = nil;
+	for(i=1; i<argc; i++){
+		if(access(argv[i], 0) == AEXIST){
+			fprint(2, "mkdir: %s already exists\n", argv[i]);
+			e = "error";
+			continue;
+		}
+		f = create(argv[i], OREAD, DMDIR | 0777L);
+		if(f < 0){
+			fprint(2, "mkdir: can't create %s: %r\n", argv[i]);
+			e = "error";
+			continue;
+		}
+		close(f);
+	}
+	exits(e);
+}