lib9: fix warning under clang 3.1

Fixes #3534.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6035054

diff --git a/src/lib9/ctime.c b/src/lib9/ctime.c
index 1bc29fbf9caf690157c551e0029adf3907913f55..6317b594bb55003e8be6a6b09c4b75f1ad9fbd87 100644 (file)
--- a/src/lib9/ctime.c
+++ b/src/lib9/ctime.c
@@ -16,8 +16,8 @@ p9ctime(long t)
        tt = t;
        tm = localtime(&tt);
        snprint(buf, sizeof buf, "%3.3s %3.3s %02d %02d:%02d:%02d %3.3s %d\n",
-               "SunMonTueWedThuFriSat"+(tm->tm_wday*3),
-               "JanFebMarAprMayJunJulAugSepOctNovDec"+(tm->tm_mon*3),
+               &"SunMonTueWedThuFriSat"[tm->tm_wday*3],
+               &"JanFebMarAprMayJunJulAugSepOctNovDec"[tm->tm_mon*3],
                tm->tm_mday,
                tm->tm_hour,
                tm->tm_min,