Port --enable-gcc-warnings to clang.

* configure.ac (nw): Remove obsolescent warnings.
These aren't needed for clang, or for gcc for that matter.
(emacs_cv_clang): New var, which tests for clang.
Omit warnings that clang is too picky about.
(GLIB_DISABLE_DEPRECATION_WARNINGS): Define this;
needed for Ubuntu 13.04 + clang + --enable-gcc-warnings.
* lib-src/etags.c: Omit unnecessary forward decls.
(print_version, print_help): Declare _Noreturn.
* lib-src/pop.c (socket_connection) [HAVE_GETADDRINFO]: Simplify.
* src/bytecode.c (exec_byte_code):
* src/regex.c:
Redo diagnostic pragmas to pacify clang, too.
* src/dbusbind.c (xd_retrieve_arg): Do not use uninitialized variable.
* src/editfns.c (Fencode_time):
* src/fileio.c (file_accessible_directory_p):
* src/font.c (font_unparse_xlfd):
Use '&"string"[index]' instead of '"string" + (index)'.
* src/undo.c (user_error): Remove; unused.

3 files changed, 24 insertions, 32 deletions

diff --git a/lib-src/ChangeLog b/lib-src/ChangeLog
index 6ff653b7be6..e565983e147 100644
--- a/lib-src/ChangeLog
+++ b/lib-src/ChangeLog
@@ -1,3 +1,10 @@
+2013-05-18  Paul Eggert  <eggert@cs.ucla.edu>
+
+	Port --enable-gcc-warnings to clang.
+	* etags.c: Omit unnecessary forward decls.
+	(print_version, print_help): Declare _Noreturn.
+	* pop.c (socket_connection) [HAVE_GETADDRINFO]: Simplify.
+
 2013-05-16  Eli Zaretskii  <eliz@gnu.org>
 
 	* update-game-score.c [WINDOWSNT]: Include "ntlib.h".
diff --git a/lib-src/etags.c b/lib-src/etags.c
index 27a853a954a..f6b173bf465 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -316,15 +316,7 @@ static void Texinfo_nodes (FILE *);
 static void Yacc_entries (FILE *);
 static void just_read_file (FILE *);
 
-static void print_language_names (void);
-static void print_version (void);
-static void print_help (argument *);
-int main (int, char **);
-
-static compressor *get_compressor_from_suffix (char *, char **);
 static language *get_language_from_langname (const char *);
-static language *get_language_from_interpreter (char *);
-static language *get_language_from_filename (char *, bool);
 static void readline (linebuffer *, FILE *);
 static long readline_internal (linebuffer *, FILE *);
 static bool nocase_tail (const char *);
@@ -346,7 +338,6 @@ static void find_entries (FILE *);
 static void free_tree (node *);
 static void free_fdesc (fdesc *);
 static void pfnote (char *, bool, char *, int, int, long);
-static void make_tag (const char *, int, bool, char *, int, int, long);
 static void invalidate_nodes (fdesc *, node **);
 static void put_entries (node *);
 
@@ -816,7 +807,7 @@ etags --help --lang=ada.");
 #ifndef VERSION
 # define VERSION "17.38.1.4"
 #endif
-static void
+static _Noreturn void
 print_version (void)
 {
   char emacs_copyright[] = COPYRIGHT;
@@ -832,7 +823,7 @@ print_version (void)
 # define PRINT_UNDOCUMENTED_OPTIONS_HELP FALSE
 #endif
 
-static void
+static _Noreturn void
 print_help (argument *argbuffer)
 {
   bool help_for_lang = FALSE;
diff --git a/lib-src/pop.c b/lib-src/pop.c
index 1f3f82baa68..a269144c915 100644
--- a/lib-src/pop.c
+++ b/lib-src/pop.c
@@ -1075,28 +1075,22 @@ socket_connection (char *host, int flags)
 	}
     } while (ret != 0);
 
-  if (ret == 0)
-    {
-      it = res;
-      while (it)
-        {
-          if (it->ai_addrlen == sizeof (addr))
-            {
-              struct sockaddr_in *in_a = (struct sockaddr_in *) it->ai_addr;
-              addr.sin_addr = in_a->sin_addr;
-              if (! connect (sock, (struct sockaddr *) &addr, sizeof (addr)))
-                break;
-            }
-          it = it->ai_next;
-        }
-      connect_ok = it != NULL;
-      if (connect_ok)
-        {
-          realhost = alloca (strlen (it->ai_canonname) + 1);
-          strcpy (realhost, it->ai_canonname);
-        }
-      freeaddrinfo (res);
+  for (it = res; it; it = it->ai_next)
+    if (it->ai_addrlen == sizeof addr)
+      {
+	struct sockaddr_in *in_a = (struct sockaddr_in *) it->ai_addr;
+	addr.sin_addr = in_a->sin_addr;
+	if (! connect (sock, (struct sockaddr *) &addr, sizeof addr))
+	  break;
+      }
+  connect_ok = it != NULL;
+  if (connect_ok)
+    {
+      realhost = alloca (strlen (it->ai_canonname) + 1);
+      strcpy (realhost, it->ai_canonname);
     }
+  freeaddrinfo (res);
+
 #else /* !HAVE_GETADDRINFO */
   do
     {