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.
* cm.c (tputs, tgoto, BC, UP): Remove extern decls. Include
tparam.h instead, since it declares them.
* cm.h (PC): Remove extern decl; tparam.h now does this.
* deps.mk (cm.o, terminfo.o): Depend on tparam.h.
* terminfo.c: Include tparam.h, to check interfaces.
(tparm): Make 1st arg a const pointer in decl. Put it at top level.
(tparam): Adjust signature to match interface in tparam.h;
this removes some undefined behavior. Check that outstring and len
are zero, which they always are with Emacs.
* tparam.h (PC, BC, UP): New extern decls.
* term.c, tparam.h: Include it.
* deps.mk (term.o, tparam.o): Depend on tparam.h.
* term.c (tputs, tgetent, tgetflag, tgetnum, tparam, tgetstr):
Move these decls to tparam.h, and make them agree with what
is actually in tparam.c. The previous trick of using incompatible
decls in different modules does not conform to the C standard.
All callers of tparam changed to use tparam's actual API.
* tparam.c (tparam1, tparam, tgoto):
Use const pointers where appropriate.
