Make Emacs functions such as Fatom 'static' by default.

Make Emacs functions such as Fatom 'static' by default.

This makes it easier for human readers (and static analyzers)
to see whether these functions can be called from other modules.
DEFUN now defines a static function.  To make the function external
so that it can be used in other C modules, use the new macro DEFUE.
* lisp.h (DEFINE_FUNC): New macro, with the old contents of DEFUN.
(DEFUN): Rewrite in terms of DEFINE_FUNC.  It now generates a
static function definition.  Use DEFUE if you want an extern one.
(DEFUE, INFUN): New macros.
(Funibyte_char_to_multibyte, Fsyntax_table_p, Finit_image_library):
(Feval_region, Fbacktrace, Ffetch_bytecode, Fswitch_to_buffer):
(Ffile_executable_p, Fmake_symbolic_link, Fcommand_execute):
(Fget_process, Fdocumentation_property, Fbyte_code, Ffile_attributes):
Remove decls, since these functions are now static.
(Funintern, Fget_internal_run_time): New decls, since these functions
were already external.
* alloc.c, buffer.c, callint.c, callproc.c, casefiddle.c, casetab.c:
* ccl.c, character.c, chartab.c, cmds.c, coding.c, data.c, dispnew.c:
* doc.c, editfns.c, emacs.c, eval.c, fileio.c, filelock.c, floatfns.c:
* fns.c, font.c, fontset.c, frame.c, image.c, indent.c:
* keyboard.c, keymap.c, lread.c:
* macros.c, marker.c, menu.c, minibuf.c, print.c, process.c, search.c:
* syntax.c, term.c, terminal.c, textprop.c, undo.c:
* window.c, xdisp.c, xfaces.c, xfns.c, xmenu.c, xsettings.c:
Mark functions with DEFUE instead of DEFUN,
if they are used in other modules.
* buffer.c (Fset_buffer_major_mode, Fdelete_overlay): New forward
decls for now-static functions.
* buffer.h (Fdelete_overlay): Remove decl.
* callproc.c (Fgetenv_internal): Mark as internal.
* composite.c (Fremove_list_of_text_properties): Remove decl.
(Fcomposition_get_gstring): New forward static decl.
* composite.h (Fcomposite_get_gstring): Remove decl.
* dired.c (Ffile_attributes): New forward static decl.
* doc.c (Fdocumntation_property): New forward static decl.
* eval.c (Ffetch_bytecode): New forward static decl.
(Funintern): Remove extern decl; now in .h file where it belongs.
* fileio.c (Fmake_symbolic_link): New forward static decl.
* image.c (Finit_image_library): New forward static decl.
* insdel.c (Fcombine_after_change_execute): Make forward decl static.
* intervals.h (Fprevious_property_change):
(Fremove_list_of_text_properties): Remove decls.
* keyboard.c (Fthis_command_keys): Remove decl.
(Fcommand_execute): New forward static decl.
* keymap.c (Flookup_key): New forward static decl.
(Fcopy_keymap): Now static.
* keymap.h (Flookup_key): Remove decl.
* process.c (Fget_process): New forward static decl.
(Fprocess_datagram_address): Mark as internal.
* syntax.c (Fsyntax_table_p): New forward static decl.
(skip_chars): Remove duplicate decl.
* textprop.c (Fprevious_property_change): New forward static decl.
* window.c (Fset_window_fringes, Fset_window_scroll_bars):
Now internal.
(Fset_window_margins, Fset_window_vscroll): New forward static decls.
* window.h (Fset_window_vscroll, Fset_window_margins): Remove decls.