treat empty TZ environment variable as GMT rather than default

this improves compatibility with the behavior of other systems and
with some applications which set an empty TZ var to disable use of
local time by mktime, etc.

diff --git a/src/time/__tz.c b/src/time/__tz.c
index 13cb1aedf9f9b1c1a5539219141c7871714b84f1..102c8bc764e1391720c3a341b8d3143c0d69bbee 100644 (file)
--- a/src/time/__tz.c
+++ b/src/time/__tz.c
@@ -125,7 +125,8 @@ static void do_tzset()
                "/usr/share/zoneinfo/\0/share/zoneinfo/\0/etc/zoneinfo/\0";
 
        s = getenv("TZ");
-       if (!s || !*s) s = "/etc/localtime";
+       if (!s) s = "/etc/localtime";
+       if (!*s) s = __gmt;
 
        if (old_tz && !strcmp(s, old_tz)) return;