tzalloc should scrub abbreviations, compatibly with tzset.

* localtime.c (settzname): Move scrubbing into ...
(scrub_abbrs): ... this new function.
(zoneinit): Use it here, rather than in settzname.
* NEWS: Document this.

NEWS

@@ -1,5 +1,14 @@
 News for the tz database
 
+Unreleased, experimental changes
+
+  Changes affecting code
+
+    tzalloc now scrubs time zone abbreviations compatibly with the way
+    that tzset always has, by replacing invalid bytes with '_' and by
+    shortening too-long abbreviations.
+
+
 Release 2014j - 2014-11-10 17:37:11 -0800
 
   Changes affecting current and future time stamps

localtime.c

@@ -284,8 +284,13 @@ settzname(void)
 			daylight = 1;
 #endif /* defined USG_COMPAT */
 	}
+}
+
+static void
+scrub_abbrs(struct state *sp)
+{
+	int i;
 	/*
-	** Finally, scrub the abbreviations.
 	** First, replace bogus characters.
 	*/
 	for (i = 0; i < sp->charcnt; ++i)
@@ -1209,7 +1214,9 @@ zoneinit(struct state *sp, char const *name)
   } else {
     int err = tzload(name, sp, true);
     if (err != 0 && name && name[0] != ':' && tzparse(name, sp, false))
-      return 0;
+      err = 0;
+    if (err == 0)
+      scrub_abbrs(sp);
     return err;
   }
 }