Port --enable-gcc-warnings to GCC 8

* configure.ac: Do not use GCC 8’s new -Wcast-align flag.
* lib-src/ebrowse.c (xmalloc):
* lib-src/emacsclient.c (xmalloc, xstrdup):
* lib-src/etags.c (xmalloc):
* lib-src/make-docfile.c (xmalloc):
* lib-src/movemail.c (xmalloc):
* src/dispnew.c (new_glyph_pool):
* src/regex.c (xmalloc):
* src/term.c (tty_menu_create):
* src/tparam.h (tparam):
Use ATTRIBUTE_MALLOC.  Also see GCC bug 85562.
* lib-src/emacsclient.c (fail):
Do not dereference a null pointer.
* src/frame.c (delete_frame):
Add a decl with UNINIT to work around GCC bug 85563.
* src/menu.h (finish_menu_items):
Do not use attribute const.
* src/regex.c (analyze_first): Use FALLTHROUGH, not a comment.

configure.ac

@@ -952,6 +952,7 @@ AS_IF([test $gl_gcc_warnings = no],
   AS_IF([test $gl_gcc_warnings = yes],
     [WERROR_CFLAGS=-Werror])
 
+  nw="$nw -Wcast-align -Wcast-align=strict" # Emacs is tricky with pointers.
   nw="$nw -Wduplicated-branches"    # Too many false alarms
   nw="$nw -Wformat-overflow=2"      # False alarms due to GCC bug 80776
   nw="$nw -Wsystem-headers"         # Don't let system headers trigger warnings

lib-src/ebrowse.c

@@ -494,7 +494,7 @@ yyerror (const char *format, const char *s)
 /* Like malloc but print an error and exit if not enough memory is
    available.  */
 
-static void *
+static void * ATTRIBUTE_MALLOC
 xmalloc (size_t nbytes)
 {
   void *p = malloc (nbytes);

lib-src/emacsclient.c

@@ -192,7 +192,7 @@ struct option longopts[] =
 
 /* Like malloc but get fatal error if memory is exhausted.  */
 
-static void *
+static void * ATTRIBUTE_MALLOC
 xmalloc (size_t size)
 {
   void *result = malloc (size);
@@ -219,7 +219,7 @@ xrealloc (void *ptr, size_t size)
 }
 
 /* Like strdup but get a fatal error if memory is exhausted. */
-char *xstrdup (const char *);
+char *xstrdup (const char *) ATTRIBUTE_MALLOC;
 
 char *
 xstrdup (const char *s)
@@ -261,7 +261,7 @@ get_current_dir_name (void)
 #endif
       )
     {
-      buf = (char *) xmalloc (strlen (pwd) + 1);
+      buf = xmalloc (strlen (pwd) + 1);
       strcpy (buf, pwd);
     }
   else
@@ -312,12 +312,15 @@ w32_get_resource (HKEY predefined, const char *key, LPDWORD type)
 
   if (RegOpenKeyEx (predefined, REG_ROOT, 0, KEY_READ, &hrootkey) == ERROR_SUCCESS)
     {
-      if (RegQueryValueEx (hrootkey, key, NULL, NULL, NULL, &cbData) == ERROR_SUCCESS)
+      if (RegQueryValueEx (hrootkey, key, NULL, NULL, NULL, &cbData)
+	  == ERROR_SUCCESS)
 	{
-	  result = (char *) xmalloc (cbData);
+	  result = xmalloc (cbData);
 
-	  if ((RegQueryValueEx (hrootkey, key, NULL, type, (LPBYTE)result, &cbData) != ERROR_SUCCESS)
-	      || (*result == 0))
+	  if ((RegQueryValueEx (hrootkey, key, NULL, type, (LPBYTE) result,
+				&cbData)
+	       != ERROR_SUCCESS)
+	      || *result == 0)
 	    {
 	      free (result);
 	      result = NULL;
@@ -369,7 +372,7 @@ w32_getenv (const char *envvar)
 
       if ((size = ExpandEnvironmentStrings (value, NULL, 0)))
 	{
-	  char *buffer = (char *) xmalloc (size);
+	  char *buffer = xmalloc (size);
 	  if (ExpandEnvironmentStrings (value, buffer, size))
 	    {
 	      /* Found and expanded.  */
@@ -700,7 +703,7 @@ fail (void)
     {
       size_t extra_args_size = (main_argc - optind + 1) * sizeof (char *);
       size_t new_argv_size = extra_args_size;
-      char **new_argv = NULL;
+      char **new_argv = xmalloc (new_argv_size);
       char *s = xstrdup (alternate_editor);
       unsigned toks = 0;
 
@@ -833,7 +836,7 @@ send_to_emacs (HSOCKET s, const char *data)
 static void
 quote_argument (HSOCKET s, const char *str)
 {
-  char *copy = (char *) xmalloc (strlen (str) * 2 + 1);
+  char *copy = xmalloc (strlen (str) * 2 + 1);
   const char *p;
   char *q;
 
@@ -1843,7 +1846,7 @@ main (int argc, char **argv)
 	       careful to expand <relpath> with the default directory
 	       corresponding to <drive>.  */
 	    {
-	      char *filename = (char *) xmalloc (MAX_PATH);
+	      char *filename = xmalloc (MAX_PATH);
 	      DWORD size;
 
 	      size = GetFullPathName (argv[i], MAX_PATH, filename, NULL);

lib-src/etags.c

@@ -7304,7 +7304,7 @@ linebuffer_setlen (linebuffer *lbp, int toksize)
 }
 
 /* Like malloc but get fatal error if memory is exhausted. */
-static void *
+static void * ATTRIBUTE_MALLOC
 xmalloc (size_t size)
 {
   void *result = malloc (size);

lib-src/make-docfile.c

@@ -123,7 +123,7 @@ memory_exhausted (void)
 
 /* Like malloc but get fatal error if memory is exhausted.  */
 
-static void *
+static void * ATTRIBUTE_MALLOC
 xmalloc (ptrdiff_t size)
 {
   void *result = malloc (size);

lib-src/movemail.c

@@ -145,7 +145,7 @@ static bool mbx_delimit_end (FILE *);
      || (!defined DISABLE_DIRECT_ACCESS && !defined MAIL_USE_SYSTEM_LOCK))
 /* Like malloc but get fatal error if memory is exhausted.  */
 
-static void *
+static void * ATTRIBUTE_MALLOC
 xmalloc (size_t size)
 {
   void *result = malloc (size);

src/dispnew.c

@@ -1280,7 +1280,7 @@ row_equal_p (struct glyph_row *a, struct glyph_row *b, bool mouse_face_p)
    with zeros.  If GLYPH_DEBUG and ENABLE_CHECKING are in effect, the global
    variable glyph_pool_count is incremented for each pool allocated.  */
 
-static struct glyph_pool *
+static struct glyph_pool * ATTRIBUTE_MALLOC
 new_glyph_pool (void)
 {
   struct glyph_pool *result = xzalloc (sizeof *result);

src/frame.c

@@ -1937,6 +1937,7 @@ delete_frame (Lisp_Object frame, Lisp_Object force)
   if (f == sf)
     {
       Lisp_Object tail;
+      Lisp_Object frame1 UNINIT;  /* This line works around GCC bug 85563.  */
       eassume (CONSP (Vframe_list));
 
       /* Look for another visible frame on the same terminal.

src/menu.h

@@ -30,7 +30,7 @@ enum {
 };
 
 extern void init_menu_items (void);
-extern void finish_menu_items (void) ATTRIBUTE_CONST;
+extern void finish_menu_items (void);
 extern void discard_menu_items (void);
 extern void save_menu_items (void);
 extern bool parse_single_submenu (Lisp_Object, Lisp_Object, Lisp_Object);

src/regex.c

@@ -212,7 +212,7 @@
 
 /* When used in Emacs's lib-src, we need xmalloc and xrealloc. */
 
-static void *
+static ATTRIBUTE_MALLOC void *
 xmalloc (size_t size)
 {
   void *val = malloc (size);
@@ -4033,8 +4033,7 @@ analyze_first (re_char *p, re_char *pend, char *fastmap,
 	    };
 	  /* Keep `p1' to allow the `on_failure_jump' we are jumping to
 	     to jump back to "just after here".  */
-	  /* Fallthrough */
-
+	  FALLTHROUGH;
 	case on_failure_jump:
 	case on_failure_keep_string_jump:
 	case on_failure_jump_nastyloop:

src/term.c

@@ -2721,7 +2721,7 @@ typedef struct tty_menu_struct
 
 /* Create a brand new menu structure.  */
 
-static tty_menu *
+static tty_menu * ATTRIBUTE_MALLOC
 tty_menu_create (void)
 {
   return xzalloc (sizeof *tty_menu_create ());

src/tparam.h

@@ -30,7 +30,7 @@ int tgetnum (const char *);
 char *tgetstr (const char *, char **);
 char *tgoto (const char *, int, int);
 
-char *tparam (const char *, char *, int, int, int, int, int);
+char *tparam (const char *, char *, int, int, int, int, int) ATTRIBUTE_MALLOC;
 
 extern char PC;
 extern char *BC;