Update timezone code from tzcode 2015g.

Update timezone code from tzcode 2015g.

This patch updates the timezone code from tzcode 2015g.  The Makefile
and README changes are based on those in Paul's patch
<https://sourceware.org/ml/libc-alpha/2015-05/msg00553.html>.

Tested for x86_64 and x86.

2016-01-06  Paul Eggert  <eggert@cs.ucla.edu>
	    Joseph Myers  <joseph@codesourcery.com>

	* timezone/private.h: Update from tzcode 2015g.
	* timezone/tzfile.h: Likewise.
	* timezone/tzselect.ksh: Likewise.
	* timezone/zdump.c: Likewise.
	* timezone/zic.c: Likewise.
	* timezone/ialloc.c: Remove file.
	* timezone/scheck.c: Likewise.
	* timezone/Makefile (extra-objs): Remove variable.
	($(objpfx)zic): Do not depend on scheck.o and ialloc.o.
	(tz-cflags): Add -DHAVE_GETTEXT -DUSE_LTZ=0
	-Wno-maybe-uninitialized.
	(CFLAGS-zdump.c): Remove -fwrapv -DNOID -DHAVE_GETTEXT.
	(CFLAGS-zic.c): Remove -DNOID -DHAVE_GETTEXT.
	(CFLAGS-ialloc.c): Remove variable.
	(CFLAGS-scheck.c): Likewise.
	* timezone/README: Update list of files from tzcode.