* lwlib/lwlib-Xaw.c: Include <stdlib.h> for 'abort' (Bug#24506).

This follows up on recent problems with the fact that config.h
includes stdlib.h etc.; some files need to include stdlib.h later.
config.h generally should limit itself to includes that are
universally safe; outside of MS-Windows, only stdbool.h makes
the cut among the files currently included.  So, move the
other includes to just the files that need them (Bug#24506).
* configure.ac (config_opsysfile): Remove, as this generic hook
is no longer needed.
* lib-src/etags.c, src/unexmacosx.c, src/w32.c, src/w32notify.c:
* src/w32proc.c (_GNU_SOURCE):
Remove, as it’s OK for config.h to do this now.
* src/conf_post.h: Include <ms-w32.h>, instead of the generic
config_opsysfile, for simplicity as this old way of configuring is
now done only for the MS-Windows port.  Do not include <ms-w32.h>
if DEFER_MS_W32_H, for the benefit of the few files that want its
effects later.  Do not include <alloca.h>, <string.h>, or
<stdlib.h>.  Other files modified to include these headers as
needed, or to not include headers that are no longer needed.
* src/lisp.h: Include <alloca.h> and <string.h> here, since
some of the inline functions need them.
* src/regex.c: Include <alloca.h> if not emacs.  (If emacs,
we can rely on SAFE_ALLOCA.)  There is no longer any need to
worry about HAVE_ALLOCA_H.
* src/unexmacosx.c: Rely on config.h not including stdlib.h.
* src/w32.c, src/w32notify.c, src/w32proc.c (DEFER_MS_W32_H):
Define before including <config.h> first, and include <ms-w32.h>
after the troublesome headers.

* lwlib/lwlib.c (lw_get_all_values): Always check the value returned by
get_widget_info.

ef33bc7 Spelling and grammar fixes
9c3dbab Fix copyright years by hand
0e96320 Update copyright year to 2016

* lib-src/Makefile.in (tagsfiles): New variable.
(TAGS): Also depend on the source files.  Use our own etags program.
* lisp/Makefile.in (ETAGS): Add EXEEXT.
(lisptagsfiles1, lisptagsfiles2, lisptagsfiles3, lisptagsfiles4):
Remove.
(tagsfiles): New, replacing lisptagsfiles1 etc.
Remove irrelevant source files here rather than in the TAGS rule.
(${ETAGS}): New rule.
(TAGS): Also depend on the etags executable.
* lwlib/Makefile.in (EXEEXT): New, set by configure.
(ETAGS): Add EXEEXT.
(${ETAGS}): New rule.
(ctagsfiles): Use "wildcard".
(TAGS): Also depend on the etags executable.
* nt/Makefile.in (ETAGS, tagsfiles): New variables.
(${ETAGS}): New rule.
(TAGS): Fix dependencies.
* oldXMenu/Makefile.in (EXEEXT): New, set by configure.
(ETAGS): New variable, replacing $TAGS.  Use our own etags program.
Remove "-t" argument.
(${ETAGS}): New rule.
(tagsfiles): New variable.
(TAGS): New rule, with proper dependencies.
* src/Makefile.in (ETAGS): Add EXEEXT.  Add a build rule.
(ctagsfiles1, ctagsfiles2): Use "wildcard".
(ctagsfiles3): Remove.
(TAGS): Depend on etags.
(../lisp/TAGS, $(lwlibdir)/TAGS): Let the rules in the relevant
directories decide if updates are needed.

Run admin/update-copyright.

Support for SunOS 4.x was removed in Emacs 23 but some cruft was left behind.
* lib-src/pop.c [sun]: Remove no-longer-needed include.
* lwlib/xlwmenu.c (SUNSO41): Remove.

Redo src/*.h so that each include file is idempotent (that is, can
be included multiple times with the latter inclusions having no
effect) and standalone (that is, can be included by itself,
with no include file other than config.h needed as a prerequisite).
This is standard practice in GNU programs nowadays.
* lwlib/lwlib-widget.h, src/buffer.h, src/category.h, src/character.h:
* src/charset.h, src/coding.h, src/commands.h, src/disptab.h:
* src/fontset.h, src/gnutls.h, src/indent.h, src/keymap.h, src/macros.h:
* src/regex.h [emacs]:
* src/syntax.h, src/systty.h, src/termhooks.h:
Include lisp.h, for Lisp_Object.
* src/buffer.h, src/category.h, src/cm.h, src/commands.h, src/disptab.h:
* src/indent.h, src/intervals.h, src/keyboard.h, src/macros.h:
* src/process.h, src/puresize.h, src/region-cache.h, src/syntax.h:
* src/syssignal.h, src/sysstdio.h, src/systty.h, src/termchar.h:
* src/termopts.h, src/tparam.h, src/unexec.h:
Protect against multiple inclusion.
* src/buffer.h: Include character.h, for STRING_CHAR.
* src/emacsgtkfixed.h (struct frame):
* src/fontset.h (struct face):
* src/region-cache.h (struct buffer):
* src/termhooks.h (struct glyph):
* src/xsettings.h (struct x_display_info):
Add possibly-forward decl.
* src/syntax.h: Include buffer.h, for BVAR.
* src/sysselect.h: Include lisp.h, for eassume.
* src/termchar.h: Include <stdio.h>, for FILE.
* src/widget.h: Include <X11/IntrinsicP.h>, for Widget.
* src/xsettings.h: Include <X11/Xlib.h>, for XEvent.

* lwlib/Makefile.in (WARN_CFLAGS):
Use built-in Make functions rather than echo+sed.