Omit ‘#include "foo.h"’ unless the file needs foo.h (Bug#21707).
In a few cases, add ‘#include "foo.h"’ if the file needs foo.h
but does not include it directly.  As a general rule, a source
file should include foo.h if it needs the interfaces that foo.h
defines.
* src/alloc.c: Don’t include process.h.  Include dispextern.h,
systime.h.
* src/atimer.c: Don’t include blockinput.h.
* src/buffer.c: Include coding.h, systime.h.  Don’t include
keyboard.h, coding.h.
* src/callint.c: Don’t include commands.h, keymap.h.
* src/callproc.c: Don’t include character.h, ccl.h, composite.h,
systty.h, termhooks.h.
* src/casetab.c: Don’t include character.h.
* src/category.c: Don’t include charset.h, keymap.h.
* src/ccl.h: Don’t include character.h.
* src/character.c: Don’t include charset.h.
* src/charset.c: Don’t include disptab.h.
* src/chartab.c: Don’t include ccl.h.
* src/cm.c: Don’t include frame.h, termhooks.h.
* src/cmds.c: Don’t include window.h, dispextern.h.
* src/coding.c: Don’t include window.h, frame.h.
* src/composite.c: Include composite.h.  Don’t include window.h,
font.h.
* src/data.c: Don’t include syssignal.h, termhooks.h, font.h.
* src/dbusbind.c: Don’t include frame.h.
* src/decompress.c: Don’t include character.h.
* src/dired.c: Don’t include character.h, commands.h, charset.h.
* src/dispnew.c: Don’t include character.h, indent.h, intervals.h,
process.h, timespec.h.  Include systime.h.
* src/doc.c: Include coding.h.  Don’t include keyboard.h.
* src/editfns.c: Include composite.h.  Don’t include frame.h.
* src/emacs.c: Include fcntl.h, coding.h.  Don’t include
commands.h, systty.h..
* src/fileio.c: Don’t include intervals.h, dispextern.h.
Include composite.h.
* src/filelock.c: Don’t include character.h, systime.h.
* src/fns.c: Don’t include time.h, commands.h, keyboard.h,
keymap.h, frame.h, blockinput.h, xterm.h.  Include composite.h.
* src/font.c: Include termhooks.h.
* src/font.h: Don’t include ccl.h, frame.h.  Add forward decls of
struct composition_it, struct face, struct glyph_string.
* src/fontset.c: Don’t include buffer.h, ccl.h, keyboard.h,
intervals.h, window.h, termhooks.h.
* src/frame.c: Don’t include character.h, commands.h, font.h.
* src/frame.h: Don’t include dispextern.h.
* src/fringe.c: Don’t include character.h.
* src/ftcrfont.c: Don’t include dispextern.h, frame.h,
character.h, charset.h, fontset.h.
* src/ftfont.c: Don’t include frame.h, blockinput.h, coding.h,
fontset.h.
* src/ftxfont.c: Don’t include dispextern.h, character.h,
charset.h, fontset.h.
* src/gfilenotify.c: Don’t include frame.h, process.h.
* src/gtkutil.c: Include dispextern.h, frame.h, systime.h.
Don’t include syssignal.h, buffer.h, charset.h, font.h.
* src/gtkutil.h: Don’t include frame.h.
* src/image.c: Include fcntl.h and stdio.h instead of sysstdio.h.
Don’t include character.h.
* src/indent.c: Don’t include keyboard.h, termchar.h.
* src/inotify.c: Don’t include character.h, frame.h.
* src/insdel.c: Include composite.h.  Don’t include blockinput.h.
* src/intervals.c: Don’t include character.h, keyboard.h.
* src/intervals.h: Don’t include dispextern.h, composite.h.
* src/keyboard.c: Don’t include sysstdio.h, disptab.h, puresize.h.
Include coding.h.
* src/keyboard.h: Don’t incldue systime.h.
* src/keymap.c: Don’t include charset.h, frame.h.
* src/lread.c: Include dispextern.h and systime.h.
Don’t include frame.h.  Include systime.h.
* src/macros.c: Don’t include commands.h, character.h, buffer.h.
* src/menu.c: Include character.h, coding.h.  Don’t include
dispextern.h.
* src/menu.h: Don’t include systime.h.
* src/minibuf.c: Don’t include commands.h, dispextern.h, syntax.h,
intervals.h, termhooks.h.
* src/print.c: Include coding.h.  Don’t include keyboard.h,
window.h, dispextern.h, termchar.h, termhooks.h, font.h.
Add forward decl of struct terminal.
* src/process.c: Don’t include termhooks.h, commands.h,
dispextern.h, composite.h.
* src/region-cache.c: Don’t include character.h.
* src/scroll.c: Don’t include keyboard.h, window.h.
* src/search.c: Don’t include category.h, commands.h.
* src/sound.c: Don’t include dispextern.h.
* src/syntax.c: Don’t include command.h, keymap.h.
* src/sysdep.c: Don’t include window.h, dispextern.h.
* src/systime.h: Use ‘#ifdef emacs’, not ‘#ifdef EMACS_LISP_H’,
* src/term.c: Don’t include systty.h, intervals.h, xterm.h.
* src/terminal.c: Include character.h.
Don’t include charset.h, coding.h.
* src/textprop.c: Don’t include character.h.
* src/undo.c: Don’t include character.h, commands.h, window.h.
* src/unexsol.c: Don’t include character.h, charset.h.
* src/widget.c: Include widget.h.  Don’t include keyboard.h,
window.h, dispextern.h, blockinput.h, character.h, font.h.
* src/widgetprv.h: Don’t include widget.h.
* src/window.c: Don’t include character.h, menu.h, intervals.h.
* src/xdisp.c: Include composite.h, systime.h.  Don’t include
macros.h, process.h.
* src/xfaces.c: Don’t include charset.h, keyboard.h, termhooks.h,
intervals.h.
* src/xfns.c: Don’t include menu.h, character.h, intervals.h,
epaths.h, fontset.h, systime.h, atimer.h, termchar.h.
* src/xfont.c: Don’t include dispextern.h, fontset.h, ccl.h.
* src/xftfont.c: Don’t include dispextern.h, character.h, fontset.h.
* src/xgselect.c: Don’t include timespec.h, frame.h.
Include systime.h.
* src/xgselect.h: Don’t include time.h.
Use a forward decl to struct timespec instead.
* src/xmenu.c: Don’t include keymap.h, character.h, charset.h,
dispextern.h.  Include systime.h.
* src/xml.c: Don’t include character.h.
* src/xrdb.c [USE_MOTIF]: Don’t include keyboard.h.
* src/xselect.c: Don’t include dispextern.h, character.h,
buffer.h, process.h.
* src/xsmfns.c: Don’t include systime.h, sysselect.h.
* src/xterm.c: Don’t include syssignal.h, charset.h, disptab.h,
intervals.h process.h, keymap.h, xgselect.h.  Include composite.h.

Remove DEFSYMs that aren't used at the C level.  Also:
* src/decompress.c (Qzlib_dll):
* src/font.c (Qunicode_sip):
* src/frame.c (Qtip_frame):
* src/ftfont.c (Qserif):
* src/gnutls.c (Qgnutls_dll):
* src/xml.c (Qlibxml2_dll):
Move from here ...
* src/w32fns.c (syms_of_w32fns): ... to here,
as these are used only on MS-Windows.

* buffer.c (syms_of_buffer):
* bytecode.c (exec_byte_code):
* callint.c (Fcall_interactively):
* callproc.c (create_temp_file):
* charset.c (define_charset_internal):
* coding.c (syms_of_coding):
* editfns.c (syms_of_editfns):
* emacs.c (main):
* fns.c (syms_of_fns):
* frame.c (delete_frame, Fframe_parameters):
* keyboard.c (syms_of_keyboard):
* keymap.c (syms_of_keymap):
* minibuf.c (read_minibuf, syms_of_minibuf):
* nsfns.m (ns_cursor_type_to_lisp):
* textprop.c (syms_of_textprop):
* xdisp.c (Fformat_mode_line, syms_of_xdisp):
* xfns.c (x_create_tip_frame, Fx_select_font):
* xml.c (parse_region):
Prefer constants like 'Qfoo' to calls like 'intern ("foo")'.
* buffer.c (syms_of_buffer): OK to do (put 'erase-buffer 'disabled
t) here now ...
(keys_of_buffer): ... instead of here.
* ftfont.c (syms_of_ftfont): Move DEFSYM of Qmono from here ...
* xfns.c (syms_of_xfns): ... to here, since ftfont.c is more
optional than xfns.c.

* xmenu.c (x_menu_set_in_use, popup_get_selection)
(Fx_menu_bar_open_internal, popup_widget_loop)
(x_activate_menubar, xg_crazy_callback_abort)
(update_frame_menubar, set_frame_menubar)
(initialize_frame_menubar, free_frame_menubar)
(create_and_show_popup_menu, x_menu_show)
(create_and_show_dialog, x_dialog_show):
* xml.c (libxml2_loaded_p, init_libxml2_functions, parse_region)
(Flibxml_parse_html_region, Flibxml_parse_xml_region):
* xrdb.c (main) [TESTRM]:
* xsettings.c (init_gsettings):
* xterm.c (XFillRectangle, xg_scroll_callback)
(xg_end_scroll_callback):
* xterm.h (x_menu_set_in_use) [USE_GTK || USE_MOTIF]:
Use bool for boolean.
* xmenu.c (TRUE): Remove; no longer used.
(show_help_event): Remove long-unused code.
(set_frame_menubar): Remove "#if 1" and corresponding "#endif" lines.

Fixes Bug#15880.
This patch also makes Q constants (e.g., Qnil) constant addresses
from the C point of view.
* make-docfile.c: Revamp to generate table of symbols, too.
Include <stdbool.h>.
(xstrdup): New function.
(main): Don't process the same file twice.
(SYMBOL): New constant in enum global_type.
(struct symbol): Turn 'value' member into a union, either v.value
for int or v.svalue for string.  All uses changed.
(add_global): New arg svalue, which overrides value, so that globals
can have a string value.
(close_emacs_global): New arg num_symbols; all uses changed.
Output lispsym decl.
(write_globals): Output symbol globals too.  Output more
ATTRIBUTE_CONST, now that Qnil etc. are C constants.
Output defsym_name table.
(scan_c_file): Move most of guts into ...
(scan_c_stream): ... new function.  Scan for DEFSYMs and
record symbols found.  Don't read past EOF if file doesn't
end in newline.
* alloc.c, bidi.c, buffer.c, bytecode.c, callint.c, casefiddle:
* casetab.c, category.c, ccl.c, charset.c, chartab.c, cmds.c, coding.c:
* composite.c, data.c, dbusbind.c, decompress.c, dired.c, dispnew.c:
* doc.c, editfns.c, emacs.c, eval.c, fileio.c, fns.c, font.c, fontset.c:
* frame.c, fringe.c, ftfont.c, ftxfont.c, gfilenotify.c, gnutls.c:
* image.c, inotify.c, insdel.c, keyboard.c, keymap.c, lread.c:
* macfont.m, macros.c, minibuf.c, nsfns.m, nsfont.m, nsimage.m:
* nsmenu.m, nsselect.m, nsterm.m, print.c, process.c, profiler.c:
* search.c, sound.c, syntax.c, term.c, terminal.c, textprop.c, undo.c:
* window.c, xdisp.c, xfaces.c, xfns.c, xftfont.c, xmenu.c, xml.c:
* xselect.c, xsettings.c, xterm.c:
Remove Q vars that represent symbols (e.g., Qnil, Qt, Qemacs).
These names are now defined automatically by make-docfile.
* alloc.c (init_symbol): New function.
(Fmake_symbol): Use it.
(c_symbol_p): New function.
(valid_lisp_object_p, purecopy): Use it.
* alloc.c (marked_pinned_symbols):
Use make_lisp_symbol instead of make_lisp_ptr.
(garbage_collect_1): Mark lispsym symbols.
(CHECK_ALLOCATED_AND_LIVE_SYMBOL): New macro.
(mark_object): Use it.
(sweep_symbols): Sweep lispsym symbols.
(symbol_uses_obj): New function.
(which_symbols): Use it.  Work for lispsym symbols, too.
(init_alloc_once): Initialize Vpurify_flag here; no need to wait,
since Qt's address is already known now.
(syms_of_alloc): Add lispsym count to symbols_consed.
* buffer.c (init_buffer_once): Compare to Qnil, not to make_number (0),
when testing whether storage is all bits zero.
* dispextern (struct image_type):
* font.c (font_property_table):
* frame.c (struct frame_parm_table, frame_parms):
* keyboard.c (scroll_bar_parts, struct event_head):
* xdisp.c (struct props):
Use XSYMBOL_INIT (Qfoo) and struct Lisp_Symbol * rather than &Qfoo and
Lisp_Object *, since Qfoo is no longer an object whose address can be
taken.  All uses changed.
* eval.c (run_hook): New function.  Most uses of Frun_hooks changed to
use it, so that they no longer need to take the address of a Lisp sym.
(syms_of_eval): Don't use DEFSYM on Vrun_hooks, as it's a variable.
* frame.c (syms_of_frame): Add defsyms for the frame_parms table.
* keyboard.c (syms_of_keyboard): Don't DEFSYM Qmenu_bar here.
DEFSYM Qdeactivate_mark before the corresponding var.
* keymap.c (syms_of_keymap): Use DEFSYM for Qmenu_bar and Qmode_line
instead of interning their symbols; this avoids duplicates.
(LISP_INITIALLY, TAG_PTR)
(DEFINE_LISP_SYMBOL_BEGIN, DEFINE_LISP_SYMBOL_END, XSYMBOL_INIT):
New macros.
(LISP_INITIALLY_ZERO): Use it.
(enum symbol_interned, enum symbol_redirect, struct Lisp_Symbol)
(EXFUN, DEFUN_ARGS_MANY, DEFUN_ARGS_UNEVALLED, DEFUN_ARGS_*):
Move decls up, to avoid forward uses.  Include globals.h earlier, too.
(make_lisp_symbol): New function.
(XSETSYMBOL): Use it.
(DEFSYM): Now just a placeholder for make-docfile.
* lread.c (DEFINE_SYMBOLS): Define, for globals.h.
(intern_sym): New function, with body taken from old intern_driver.
(intern_driver): Use it.  Last arg is now Lisp integer, not ptrdiff_t.
All uses changed.
(define_symbol): New function.
(init_obarray): Define the C symbols taken from lispsym.
Use plain DEFSYM for Qt and Qnil.
* syntax.c (init_syntax_once): No need to worry about
Qchar_table_extra_slots.

Run admin/update-copyright.

* decompress.c, gnutls.c, image.c, xml.c:
If WINDOWSNT, use '#define FOO fn_FOO' to wrap dll functions,
rather than the inverse when not WINDOWSNT.  This isolates the
fn_* business into the WINDOWSNT-specific section of the code,
which makes it easier to maintain the generic code.
* decompress.c (DEF_ZLIB_FN, LOAD_ZLIB_FN):
* gnutls.c (DEF_GNUTLS_FN, LOAD_GNUTLS_FN):
* image.c (DEF_IMGLIB_FN, LOAD_IMGLIB_FN):
* xml.c (DEF_XML2_FN, LOAD_XML2_FN):
Remove.  All uses replaced by DEF_DLL_FN.
* w32.h (DEF_DLL_FN, LOAD_DLL_FN): New macros.

* doc/lispref/text.texi (Parsing HTML/XML): Document new optional parameter
'discard-comments' of 'libxml-parse(html|xml)-region'.

* src/xml.c (parse_region): Take care of new optional parameter
'discard-comments' of 'libxml-parse(html|xml)-region'.
(Flibxml_parse_html_region, Flibxml_parse_xml_region): New
optional parameter 'discard-comments'.

* test/automated/libxml-tests.el
(libxml-tests--data-comments-preserved): Renamed from
'libxml-tests--data'.
(libxml-tests--data-comments-discarded): New.
(libxml-tests): Check whether 'libxml-parse-xml-region' is
discarding comments correctly.

* src/xml.c (parse_region): Do not forget the first document child.

* test/automated/libxml-tests.el: New file.