Pacify gcc 11.1.1 -Wanalyzer-null-argument

* lib-src/etags.c (regexp): Omit member force_explicit_name,
since it’s always true.  All uses removed.  This lets us
remove calls to strlen (name) where GCC isn’t smart enough
to deduce that name must be nonnull.
* lib-src/movemail.c (main): Fix bug that could cause
link (tempname, NULL) to be called.
* src/emacs.c (argmatch): Break check into two ‘if’s,
since GCC doesn’t seem to be smart enough to check the single ‘if’.
* src/gtkutil.c (xg_update_menu_item): Fix bug where strcmp
could be given a NULL arg.
* src/xfont.c (xfont_list_family): Use nonnull value for dummy
initial value.

lib-src/etags.c

@@ -340,7 +340,6 @@ typedef struct regexp
   struct re_pattern_buffer *pat; /* the compiled pattern */
   struct re_registers regs;	/* re registers */
   bool error_signaled;		/* already signaled for this regexp */
-  bool force_explicit_name;	/* do not allow implicit tag name */
   bool ignore_case;		/* ignore case when matching */
   bool multi_line;		/* do a multi-line match on the whole file */
 } regexp;
@@ -6910,7 +6909,6 @@ add_regex (char *regexp_pattern, language *lang)
   struct re_pattern_buffer *patbuf;
   regexp *rp;
   bool
-    force_explicit_name = true, /* do not use implicit tag names */
     ignore_case = false,	/* case is significant */
     multi_line = false,		/* matches are done one line at a time */
     single_line = false;	/* dot does not match newline */
@@ -6949,7 +6947,8 @@ add_regex (char *regexp_pattern, language *lang)
       case 'N':
 	if (modifiers == name)
 	  error ("forcing explicit tag name but no name, ignoring");
-	force_explicit_name = true;
+	/* This option has no effect and is present only for backward
+	   compatibility.  */
 	break;
       case 'i':
 	ignore_case = true;
@@ -7004,7 +7003,6 @@ add_regex (char *regexp_pattern, language *lang)
   p_head->pat = patbuf;
   p_head->name = savestr (name);
   p_head->error_signaled = false;
-  p_head->force_explicit_name = force_explicit_name;
   p_head->ignore_case = ignore_case;
   p_head->multi_line = multi_line;
 }
@@ -7144,20 +7142,15 @@ regex_tag_multiline (void)
 		name = NULL;
 	      else /* make a named tag */
 		name = substitute (buffer, rp->name, &rp->regs);
-	      if (rp->force_explicit_name)
-		{
-		  /* Force explicit tag name, if a name is there. */
-		  pfnote (name, true, buffer + linecharno,
-			  charno - linecharno + 1, lineno, linecharno);
 
-		  if (debug)
-		    fprintf (stderr, "%s on %s:%"PRIdMAX": %s\n",
-			     name ? name : "(unnamed)", curfdp->taggedfname,
-			     lineno, buffer + linecharno);
-		}
-	      else
-		make_tag (name, strlen (name), true, buffer + linecharno,
-			  charno - linecharno + 1, lineno, linecharno);
+	      /* Force explicit tag name, if a name is there. */
+	      pfnote (name, true, buffer + linecharno,
+		      charno - linecharno + 1, lineno, linecharno);
+
+	      if (debug)
+		fprintf (stderr, "%s on %s:%"PRIdMAX": %s\n",
+			 name ? name : "(unnamed)", curfdp->taggedfname,
+			 lineno, buffer + linecharno);
 	      break;
 	    }
 	}
@@ -7471,18 +7464,14 @@ readline (linebuffer *lbp, FILE *stream)
 		name = NULL;
 	      else /* make a named tag */
 		name = substitute (lbp->buffer, rp->name, &rp->regs);
-	      if (rp->force_explicit_name)
-		{
-		  /* Force explicit tag name, if a name is there. */
-		  pfnote (name, true, lbp->buffer, match, lineno, linecharno);
-		  if (debug)
-		    fprintf (stderr, "%s on %s:%"PRIdMAX": %s\n",
-			     name ? name : "(unnamed)", curfdp->taggedfname,
-			     lineno, lbp->buffer);
-		}
-	      else
-		make_tag (name, strlen (name), true,
-			  lbp->buffer, match, lineno, linecharno);
+
+	      /* Force explicit tag name, if a name is there. */
+	      pfnote (name, true, lbp->buffer, match, lineno, linecharno);
+
+	      if (debug)
+		fprintf (stderr, "%s on %s:%"PRIdMAX": %s\n",
+			 name ? name : "(unnamed)", curfdp->taggedfname,
+			 lineno, lbp->buffer);
 	      break;
 	    }
 	}

lib-src/movemail.c

@@ -270,6 +270,7 @@ main (int argc, char **argv)
 	 You might also wish to verify that your system is one which
 	 uses lock files for this purpose.  Some systems use other methods.  */
 
+      bool lockname_unlinked = false;
       inname_len = strlen (inname);
       lockname = xmalloc (inname_len + sizeof ".lock");
       strcpy (lockname, inname);
@@ -312,15 +313,10 @@ main (int argc, char **argv)
 	     Five minutes should be good enough to cope with crashes
 	     and wedgitude, and long enough to avoid being fooled
 	     by time differences between machines.  */
-	  if (stat (lockname, &st) >= 0)
-	    {
-	      time_t now = time (0);
-	      if (st.st_ctime < now - 300)
-		{
-		  unlink (lockname);
-		  lockname = 0;
-		}
-	    }
+	  if (!lockname_unlinked
+	      && stat (lockname, &st) == 0
+	      && st.st_ctime < time (0) - 300)
+	    lockname_unlinked = unlink (lockname) == 0 || errno == ENOENT;
 	}
 
       delete_lockname = lockname;

src/emacs.c

@@ -670,7 +670,9 @@ argmatch (char **argv, int argc, const char *sstr, const char *lstr,
     }
   arglen = (valptr != NULL && (p = strchr (arg, '=')) != NULL
 	    ? p - arg : strlen (arg));
-  if (lstr == 0 || arglen < minlen || strncmp (arg, lstr, arglen) != 0)
+  if (!lstr)
+    return 0;
+  if (arglen < minlen || strncmp (arg, lstr, arglen) != 0)
     return 0;
   else if (valptr == NULL)
     {

src/gtkutil.c

@@ -3221,7 +3221,7 @@ xg_update_menu_item (widget_value *val,
       gtk_label_set_text (wkey, utf8_key);
     }
 
-  if (! old_label || strcmp (utf8_label, old_label) != 0)
+  if (utf8_label && (! old_label || strcmp (utf8_label, old_label) != 0))
     {
       label_changed = true;
       gtk_label_set_text (wlbl, utf8_label);

src/xfont.c

@@ -596,7 +596,10 @@ xfont_list_family (struct frame *f)
   char **names;
   int num_fonts, i;
   Lisp_Object list;
-  char *last_family UNINIT;
+  char const *last_family;
+#if defined GCC_LINT || defined lint
+  last_family = "";
+#endif
   int last_len;
 
   block_input ();