Simplify some ALL_STATE and PCTS ifdefs.

* Makefile (GCC_DEBUG_FLAGS): Add -Wno-address and -Wno-cast-qual.
Otherwise, GCC 4.8.1 complains about some of the following changes.
* localtime.c (wildabbr): Now const.  This is a tiny bit more
efficient, POSIX allows it, and the ALL_STATE simplifications
below make use of it.  All uses changed to cast if needed.
(settzname, tzload, localsub, gmtsub, timesub, time2sub, time1):
Protect less code with ALL_STATE; this is simpler and doesn't
change behavior (or, these days, efficiency).
(time1): Simplify the PCTS ifdef, and explain what PCTS is.