Re: Emacs release branch warnings with GCC 8

[Paul Eggert <eggert@cs.ucla.edu>]

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On 04/30/2018 12:58 PM, Eli Zaretskii wrote:
> I'd prefer to leave -Wsuggest-attribute=malloc out on the release
> branch, for now.

OK, I installed the attached backport into the emacs-26 branch; it does 
the minimum to silence the diagnostics, without adding the new GCC 8 
warning options.

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From 65ac27783a959a8339c2aab0f1e54d9b508a1f1f Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 30 Apr 2018 17:17:11 -0700
Subject: [PATCH] Port --enable-gcc-warnings to GCC 8

Backport from master.
* 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.
---
 lib-src/emacsclient.c | 2 +-
 src/frame.c           | 1 +
 src/menu.h            | 2 +-
 src/regex.c           | 3 +--
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib-src/emacsclient.c b/lib-src/emacsclient.c
index 574bec850f..b139b2fe3f 100644
--- a/lib-src/emacsclient.c
+++ b/lib-src/emacsclient.c
@@ -700,7 +700,7 @@ 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;
 
diff --git a/src/frame.c b/src/frame.c
index cee775c6fa..0a6ca26f5d 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -1933,6 +1933,7 @@ 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.
diff --git a/src/menu.h b/src/menu.h
index 4c4ac83424..1aa53f7454 100644
--- a/src/menu.h
+++ b/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);
diff --git a/src/regex.c b/src/regex.c
index e8b99f6f02..4f9df68a9f 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -4038,8 +4038,7 @@ analyze_first (const_re_char *p, const_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:
-- 
2.17.0