fix parsing offsets after long timezone names

TZ containg a timezone name with >TZNAME_MAX characters currently
breaks musl's timezone parsing. getname() stops after TZNAME_MAX
characters. getoff() will consume no characters (because the next
character is not a digit) and incorrectly return 0. Then, because
there are remaining alphabetic characters, __daylight == 1, and
dst_off == -3600.

getname() must consume the entire timezone name, even if it will not
fit in d/__tzname, so when it returns, s points to the offset digits.

src/time/__tz.c

@@ -86,15 +86,15 @@ static void getname(char *d, const char **p)
 	int i;
 	if (**p == '<') {
 		++*p;
-		for (i=0; (*p)[i] && (*p)[i]!='>' && i<TZNAME_MAX; i++)
+		for (i=0; (*p)[i] && (*p)[i]!='>'; i++)
-			d[i] = (*p)[i];
+			if (i<TZNAME_MAX) d[i] = (*p)[i];
 		if ((*p)[i]) ++*p;
 	} else {
-		for (i=0; ((*p)[i]|32)-'a'<26U && i<TZNAME_MAX; i++)
+		for (i=0; ((*p)[i]|32)-'a'<26U; i++)
-			d[i] = (*p)[i];
+			if (i<TZNAME_MAX) d[i] = (*p)[i];
 	}
 	*p += i;
-	d[i] = 0;
+	d[i<TZNAME_MAX?i:TZNAME_MAX] = 0;
 }
 
 #define VEC(...) ((const unsigned char[]){__VA_ARGS__})