Omit IF_LINT code that no longer seems needed

Nowadays GCC is smarter, or the Emacs code has mutated, or both,
and now is as good a time as any to remove uses of IF_LINT that
now seem to be unnecessary.
* lib-src/emacsclient.c (set_local_socket):
* lib-src/movemail.c (main) [MAIL_USE_MAILLOCK && HAVE_TOUCHLOCK]:
* src/buffer.c (fix_start_end_in_overlays, fix_overlays_before):
* src/casefiddle.c (casify_region):
* src/charset.c (load_charset_map):
* src/coding.c (decode_coding_object, encode_coding_object):
* src/data.c (Fmake_variable_buffer_local, Fmake_local_variable)
(cons_to_unsigned, cons_to_signed):
* src/frame.c (make_frame, x_set_frame_parameters):
* src/keyboard.c (read_event_from_main_queue):
* src/regex.c (regex_compile):
* src/syntax.c (back_comment):
* src/window.c (Frecenter):
* src/xfaces.c (Fx_list_fonts):
Remove IF_LINT that no longer seems necessary.
* src/image.c (png_load_body, jpeg_load_body): Simplify use of IF_LINT.
* src/keyboard.c (read_char): Use IF_LINT (volatile) rather than
a pragma dance to pacify GCC -Wclobbered.
* src/xdisp.c (x_produce_glyphs): Rewrite to avoid need for IF_LINT.

* src/xterm.c (x_connection_closed): Now _Noreturn, which should
mean we do not need IF_LINT any more.
(x_io_error_quitter): Now _Noreturn.  Put an 'assume (false)’
at the end, to forestall warnings from older compilers.

lib-src/emacsclient.c

@@ -1195,7 +1195,7 @@ set_local_socket (const char *local_socket_name)
     int use_tmpdir = 0;
     int saved_errno;
     const char *server_name = local_socket_name;
-    const char *tmpdir IF_LINT ( = NULL);
+    const char *tmpdir;
     char *tmpdir_storage = NULL;
     char *socket_name_storage = NULL;
 

lib-src/movemail.c

@@ -338,7 +338,7 @@ main (int argc, char **argv)
       int lockcount = 0;
       int status = 0;
 #if defined (MAIL_USE_MAILLOCK) && defined (HAVE_TOUCHLOCK)
-      time_t touched_lock IF_LINT (= 0);
+      time_t touched_lock;
 #endif
 
       if (setuid (getuid ()) < 0 || setregid (-1, real_gid) < 0)

src/buffer.c

@@ -3552,8 +3552,8 @@ void
 fix_start_end_in_overlays (register ptrdiff_t start, register ptrdiff_t end)
 {
   Lisp_Object overlay;
-  struct Lisp_Overlay *before_list IF_LINT (= NULL);
-  struct Lisp_Overlay *after_list IF_LINT (= NULL);
+  struct Lisp_Overlay *before_list;
+  struct Lisp_Overlay *after_list;
   /* These are either nil, indicating that before_list or after_list
      should be assigned, or the cons cell the cdr of which should be
      assigned.  */
@@ -3700,7 +3700,7 @@ fix_overlays_before (struct buffer *bp, ptrdiff_t prev, ptrdiff_t pos)
   /* If parent is nil, replace overlays_before; otherwise, parent->next.  */
   struct Lisp_Overlay *tail = bp->overlays_before, *parent = NULL, *right_pair;
   Lisp_Object tem;
-  ptrdiff_t end IF_LINT (= 0);
+  ptrdiff_t end;
 
   /* After the insertion, the several overlays may be in incorrect
      order.  The possibility is that, in the list `overlays_before',

src/casefiddle.c

@@ -196,7 +196,7 @@ casify_region (enum case_action flag, Lisp_Object b, Lisp_Object e)
   ptrdiff_t start_byte;
 
   /* Position of first and last changes.  */
-  ptrdiff_t first = -1, last IF_LINT (= 0);
+  ptrdiff_t first = -1, last;
 
   ptrdiff_t opoint = PT;
   ptrdiff_t opoint_byte = PT_BYTE;

src/charset.c

@@ -240,7 +240,7 @@ struct charset_map_entries
 static void
 load_charset_map (struct charset *charset, struct charset_map_entries *entries, int n_entries, int control_flag)
 {
-  Lisp_Object vec IF_LINT (= Qnil), table IF_LINT (= Qnil);
+  Lisp_Object vec, table IF_LINT (= Qnil);
   unsigned max_code = CHARSET_MAX_CODE (charset);
   bool ascii_compatible_p = charset->ascii_compatible_p;
   int min_char, max_char, nonascii_min_char;

src/coding.c

@@ -8015,12 +8015,12 @@ decode_coding_object (struct coding_system *coding,
 		      Lisp_Object dst_object)
 {
   ptrdiff_t count = SPECPDL_INDEX ();
-  unsigned char *destination IF_LINT (= NULL);
-  ptrdiff_t dst_bytes IF_LINT (= 0);
+  unsigned char *destination;
+  ptrdiff_t dst_bytes;
   ptrdiff_t chars = to - from;
   ptrdiff_t bytes = to_byte - from_byte;
   Lisp_Object attrs;
-  ptrdiff_t saved_pt = -1, saved_pt_byte IF_LINT (= 0);
+  ptrdiff_t saved_pt = -1, saved_pt_byte;
   bool need_marker_adjustment = 0;
   Lisp_Object old_deactivate_mark;
 
@@ -8198,7 +8198,7 @@ encode_coding_object (struct coding_system *coding,
   ptrdiff_t chars = to - from;
   ptrdiff_t bytes = to_byte - from_byte;
   Lisp_Object attrs;
-  ptrdiff_t saved_pt = -1, saved_pt_byte IF_LINT (= 0);
+  ptrdiff_t saved_pt = -1, saved_pt_byte;
   bool need_marker_adjustment = 0;
   bool kill_src_buffer = 0;
   Lisp_Object old_deactivate_mark;

src/data.c

@@ -1614,8 +1614,8 @@ The function `default-value' gets the default value and `set-default' sets it.
 {
   struct Lisp_Symbol *sym;
   struct Lisp_Buffer_Local_Value *blv = NULL;
-  union Lisp_Val_Fwd valcontents IF_LINT (= {LISP_INITIALLY_ZERO});
-  bool forwarded IF_LINT (= 0);
+  union Lisp_Val_Fwd valcontents;
+  bool forwarded;
 
   CHECK_SYMBOL (variable);
   sym = XSYMBOL (variable);
@@ -1692,8 +1692,8 @@ Instead, use `add-hook' and specify t for the LOCAL argument.  */)
   (Lisp_Object variable)
 {
   Lisp_Object tem;
-  bool forwarded IF_LINT (= 0);
-  union Lisp_Val_Fwd valcontents IF_LINT (= {LISP_INITIALLY_ZERO});
+  bool forwarded;
+  union Lisp_Val_Fwd valcontents;
   struct Lisp_Symbol *sym;
   struct Lisp_Buffer_Local_Value *blv = NULL;
 
@@ -2458,7 +2458,7 @@ uintmax_t
 cons_to_unsigned (Lisp_Object c, uintmax_t max)
 {
   bool valid = 0;
-  uintmax_t val IF_LINT (= 0);
+  uintmax_t val;
   if (INTEGERP (c))
     {
       valid = 0 <= XINT (c);
@@ -2511,7 +2511,7 @@ intmax_t
 cons_to_signed (Lisp_Object c, intmax_t min, intmax_t max)
 {
   bool valid = 0;
-  intmax_t val IF_LINT (= 0);
+  intmax_t val;
   if (INTEGERP (c))
     {
       val = XINT (c);

src/frame.c

@@ -609,7 +609,7 @@ make_frame (bool mini_p)
 {
   Lisp_Object frame;
   struct frame *f;
-  struct window *rw, *mw IF_LINT (= NULL);
+  struct window *rw, *mw;
   Lisp_Object root_window;
   Lisp_Object mini_window;
 
@@ -3089,7 +3089,7 @@ x_set_frame_parameters (struct frame *f, Lisp_Object alist)
   /* If both of these parameters are present, it's more efficient to
      set them both at once.  So we wait until we've looked at the
      entire list before we set them.  */
-  int width IF_LINT (= 0), height IF_LINT (= 0);
+  int width, height;
   bool width_change = false, height_change = false;
 
   /* Same here.  */

src/image.c

@@ -5895,12 +5895,13 @@ static bool
 png_load_body (struct frame *f, struct image *img, struct png_load_context *c)
 {
   Lisp_Object specified_file;
-  Lisp_Object specified_data;
+  /* IF_LINT (volatile) works around GCC bug 54561.  */
+  Lisp_Object IF_LINT (volatile) specified_data;
+  FILE * IF_LINT (volatile) fp = NULL;
   int x, y;
   ptrdiff_t i;
   png_struct *png_ptr;
   png_info *info_ptr = NULL, *end_info = NULL;
-  FILE *fp = NULL;
   png_byte sig[8];
   png_byte *pixels = NULL;
   png_byte **rows = NULL;
@@ -5922,7 +5923,6 @@ png_load_body (struct frame *f, struct image *img, struct png_load_context *c)
   /* Find out what file to load.  */
   specified_file = image_spec_value (img->spec, QCfile, NULL);
   specified_data = image_spec_value (img->spec, QCdata, NULL);
-  IF_LINT (Lisp_Object volatile specified_data_volatile = specified_data);
 
   if (NILP (specified_data))
     {
@@ -6018,10 +6018,6 @@ png_load_body (struct frame *f, struct image *img, struct png_load_context *c)
       return 0;
     }
 
-  /* Silence a bogus diagnostic; see GCC bug 54561.  */
-  IF_LINT (fp = c->fp);
-  IF_LINT (specified_data = specified_data_volatile);
-
   /* Read image info.  */
   if (!NILP (specified_data))
     png_set_read_fn (png_ptr, &tbr, png_read_from_memory);
@@ -6672,9 +6668,9 @@ jpeg_load_body (struct frame *f, struct image *img,
 		struct my_jpeg_error_mgr *mgr)
 {
   Lisp_Object specified_file;
-  Lisp_Object specified_data;
-  /* The 'volatile' silences a bogus diagnostic; see GCC bug 54561.  */
-  FILE * IF_LINT (volatile) fp = NULL;
+  /* IF_LINT (volatile) works around GCC bug 54561.  */
+  Lisp_Object IF_LINT (volatile) specified_data;
+  FILE *volatile fp = NULL;
   JSAMPARRAY buffer;
   int row_stride, x, y;
   unsigned long *colors;
@@ -6687,7 +6683,6 @@ jpeg_load_body (struct frame *f, struct image *img,
   /* Open the JPEG file.  */
   specified_file = image_spec_value (img->spec, QCfile, NULL);
   specified_data = image_spec_value (img->spec, QCdata, NULL);
-  IF_LINT (Lisp_Object volatile specified_data_volatile = specified_data);
 
   if (NILP (specified_data))
     {
@@ -6751,9 +6746,6 @@ jpeg_load_body (struct frame *f, struct image *img,
       return 0;
     }
 
-  /* Silence a bogus diagnostic; see GCC bug 54561.  */
-  IF_LINT (specified_data = specified_data_volatile);
-
   /* Create the JPEG decompression object.  Let it read from fp.
 	 Read the JPEG image header.  */
   jpeg_CreateDecompress (&mgr->cinfo, JPEG_LIB_VERSION, sizeof *&mgr->cinfo);

src/keyboard.c

@@ -2122,7 +2122,7 @@ read_event_from_main_queue (struct timespec *end_time,
 {
   Lisp_Object c = Qnil;
   sys_jmp_buf save_jump;
-  KBOARD *kb IF_LINT (= NULL);
+  KBOARD *kb;
 
  start:
 
@@ -2280,11 +2280,6 @@ read_decoded_event_from_main_queue (struct timespec *end_time,
     }
 }
 
-#if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wclobbered"
-#endif
-
 /* Read a character from the keyboard; call the redisplay if needed.  */
 /* commandflag 0 means do not autosave, but do redisplay.
    -1 means do not redisplay, but do autosave.
@@ -2317,7 +2312,9 @@ read_char (int commandflag, Lisp_Object map,
 	   Lisp_Object prev_event,
 	   bool *used_mouse_menu, struct timespec *end_time)
 {
-  Lisp_Object c;
+  /* IF_LINT (volatile) works around GCC bug 54561.  */
+  Lisp_Object IF_LINT (volatile) c;
+
   ptrdiff_t jmpcount;
   sys_jmp_buf local_getcjmp;
   sys_jmp_buf save_jump;
@@ -3125,10 +3122,6 @@ read_char (int commandflag, Lisp_Object map,
   return c;
 }
 
-#if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
-# pragma GCC diagnostic pop
-#endif
-
 /* Record a key that came from a mouse menu.
    Record it for echoing, for this-command-keys, and so on.  */
 

src/regex.c

@@ -2465,9 +2465,9 @@ regex_compile (const_re_char *pattern, size_t size, reg_syntax_t syntax,
 
   /* These hold the values of p, pattern, and pend from the main
      pattern when we have pushed into a subpattern.  */
-  re_char *main_p IF_LINT (= NULL);
-  re_char *main_pattern IF_LINT (= NULL);
-  re_char *main_pend IF_LINT (= NULL);
+  re_char *main_p;
+  re_char *main_pattern;
+  re_char *main_pend;
 
 #ifdef DEBUG
   debug++;

src/syntax.c

@@ -708,7 +708,7 @@ back_comment (ptrdiff_t from, ptrdiff_t from_byte, ptrdiff_t stop,
   ptrdiff_t comment_end = from;
   ptrdiff_t comment_end_byte = from_byte;
   ptrdiff_t comstart_pos = 0;
-  ptrdiff_t comstart_byte IF_LINT (= 0);
+  ptrdiff_t comstart_byte;
   /* Place where the containing defun starts,
      or 0 if we didn't come across it yet.  */
   ptrdiff_t defun_start = 0;

src/window.c

@@ -5693,7 +5693,7 @@ and redisplay normally--don't erase and redraw the frame.  */)
   struct buffer *buf = XBUFFER (w->contents);
   bool center_p = false;
   ptrdiff_t charpos, bytepos;
-  EMACS_INT iarg IF_LINT (= 0);
+  EMACS_INT iarg;
   int this_scroll_margin;
 
   if (buf != current_buffer)

src/xdisp.c

@@ -27342,18 +27342,21 @@ x_produce_glyphs (struct it *it)
 	  int leftmost, rightmost, lowest, highest;
 	  int lbearing, rbearing;
 	  int i, width, ascent, descent;
-	  int c IF_LINT (= 0); /* cmp->glyph_len can't be zero; see Bug#8512 */
+	  int c;
 	  XChar2b char2b;
 	  struct font_metrics *pcm;
 	  ptrdiff_t pos;
 
-	  for (glyph_len = cmp->glyph_len; glyph_len > 0; glyph_len--)
-	    if ((c = COMPOSITION_GLYPH (cmp, glyph_len - 1)) != '\t')
-	      break;
+	  eassume (0 < glyph_len); /* See Bug#8512.  */
+	  do
+	    c = COMPOSITION_GLYPH (cmp, --glyph_len);
+	  while (c == '\t' && 0 < glyph_len);
+
 	  bool right_padded = glyph_len < cmp->glyph_len;
 	  for (i = 0; i < glyph_len; i++)
 	    {
-	      if ((c = COMPOSITION_GLYPH (cmp, i)) != '\t')
+	      c = COMPOSITION_GLYPH (cmp, i);
+	      if (c != '\t')
 		break;
 	      cmp->offsets[i * 2] = cmp->offsets[i * 2 + 1] = 0;
 	    }

src/xfaces.c

@@ -1519,7 +1519,7 @@ the WIDTH times as wide as FACE on FRAME.  */)
    Lisp_Object maximum, Lisp_Object width)
 {
   struct frame *f;
-  int size, avgwidth IF_LINT (= 0);
+  int size, avgwidth;
 
   check_window_system (NULL);
   CHECK_STRING (pattern);

src/xterm.c

@@ -9393,7 +9393,7 @@ static char *error_msg;
 /* Handle the loss of connection to display DPY.  ERROR_MESSAGE is
    the text of an error message that lead to the connection loss.  */
 
-static void
+static _Noreturn void
 x_connection_closed (Display *dpy, const char *error_message, bool ioerror)
 {
   struct x_display_info *dpyinfo = x_display_info_for_display (dpy);
@@ -9491,9 +9491,6 @@ For details, see etc/PROBLEMS.\n",
   unbind_to (idx, Qnil);
   clear_waiting_for_input ();
 
-  /* Tell GCC not to suggest attribute 'noreturn' for this function.  */
-  IF_LINT (if (! terminal_list) return; )
-
   /* Here, we absolutely have to use a non-local exit (e.g. signal, throw,
      longjmp), because returning from this function would get us back into
      Xlib's code which will directly call `exit'.  */
@@ -9559,7 +9556,7 @@ x_error_quitter (Display *display, XErrorEvent *event)
    It kills all frames on the display that we lost touch with.
    If that was the only one, it prints an error message and kills Emacs.  */
 
-static int
+static _Noreturn int
 x_io_error_quitter (Display *display)
 {
   char buf[256];
@@ -9567,7 +9564,7 @@ x_io_error_quitter (Display *display)
   snprintf (buf, sizeof buf, "Connection lost to X server '%s'",
 	    DisplayString (display));
   x_connection_closed (display, buf, true);
-  return 0;
+  assume (false);
 }
 
 /* Changing the font of the frame.  */