Pacify gcc -Wmissing-variable-declarations

This is a new warning diagnostic in GCC 14.
* lib-src/etags.c (mercury_heuristics_ratio):
* src/pgtkselect.c, src/xselect.c (selection_request_stack):
* src/xselect.c (outstanding_transfers):
* src/xterm.c (pending_selection_requests)
(x_dnd_waiting_for_motif_finish_display):
Now static.
* lib-src/make-docfile.c (close_emacs_globals):
Arrange for lispsym to be declared with extern first,
when compiling lread.c.
* src/alloc.c (gdb_make_enums_visible) [__GNUC__]:
* src/emacs.c (RCS_Id):
* src/keyboard.c (stop_character):
* src/print.c (print_output_debug_flag):
Now declared with extern first.
* src/lisp.h (DEFINE_GDB_SYMBOL_BEGIN) [MAIN_PROGRAM]:
Arrange for ID to be declared extern first.
* src/lisp.h (garbage_collection_inhibited):
* src/xterm.h (x_frame_parm_handlers):
Declare here, so that its interface is properly checked.  Other decls
removed.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/pgtkselect.c b/src/pgtkselect.c
index b0ab15c6069..271411b87ca 100644
--- a/src/pgtkselect.c
+++ b/src/pgtkselect.c
@@ -353,7 +353,7 @@ struct pgtk_selection_request
 /* Stack of selections currently being processed.
    NULL if all requests have been fully processed.  */
 
-struct pgtk_selection_request *selection_request_stack;
+static struct pgtk_selection_request *selection_request_stack;
 
 static void
 pgtk_push_current_selection_request (struct selection_input_event *se,