Plus a few more .gitignore improvements.
* .gitignore: Add copyright notice, since it's big enough.
Put exceptions immediately after the patterns they're exceptions
to, to make them easier to follow.
Give four exceptions for the Makefile pattern.
Ignore /confdefs.h, test/indent/*.new, TAGS, GPATH, GSYMS, GRTAGS,
GTAGS, ID, *.exe, some nextstep-related files,
jisx2131-filter, *.orig, *.rej, etc/emacs.tmpdesktop, *.in-h
_* (except for build-aux/snippet/_Noreturn.h), /bin/, /BIN/,
/data/, etc/icons/, lib/cxxdefs.h, lib/SYS/, /libexec/, /lock/,
/README.W32, /share/, /site-lisp/, src/gdb.ini, /var/.
Ignore /configure.lineno, since POSIX requires
LINENO only with the User Portability Utilities option.
Ignore *cust-load.el and *loaddefs.el only under lisp.
Ignore core files of various flavors.
Do not ignore etc/refcards/gnus-logo.pdf.
This fixes some unwanted 'git status' output after 'make docs'.
* .gitignore: Add **/Makefile, **/makefile.
Remove Makefile, makefile.
Add doc/*/*.xxx rules for the usual kinds of documentation outputs
and temporaries. Add doc/misc/cc-mode.ss.
* doc/emacs/.gitignore, doc/lispref/.gitignore, doc/misc/.gitignore:
* lwlib/.gitignore, oldXMenu/.gitignore:
Remove, as these .gitignore files are no longer needed.
* doc/lispintro/.gitignore: Replace with list of exceptional PDF files.
around image definitions and prototypes.
(gamma_correct) [WINDOWSNT]: New prototype.
* w32term.c (x_make_frame_visible): Replace call to
input_poll_signal with poll_for_input.
* window.c [WINDOWSNT]: Include w32term.h.
* xdisp.c [WINDOWSNT]: Include w32term.h.
* makefile.nt: Add dependencies on w32gui.h.
(OBJ1): Include atimer.obj.
($(BLD)\atimer.obj): New dependency rule.
* w32.c (sigmask): New function (does nothing).
(sigunblock): Ditto.
* frame.c [WINDOWSNT]: Include w32term.h.
* w32gui.h (struct W32FontStruct): Add ascent and descent slots.
* lread.c (syms_of_lread): Fix literal newlines.
* emacs.c (USAGE): Split into USAGE1 and USAGE2, to work-around
the string constant limit (2048 bytes) in MSVC.
(main): Ditto.
