-std versus -std1 for Tru64 cc

[Paul Eggert]

I installed this as per the recent discussion on the autoconf mailing list:

2004-01-15  Paul Eggert  <address@hidden>

        * lib/autoconf/c.m4 (_AC_PROG_CC_STDC): Try -std, not -std1, since
        -std1 disables some useful extensions on Tru64.  Problem reported
        by N. Lichtmaier in
        <http://mail.gnu.org/archive/html/autoconf/2004-01/msg00100.html>.

Index: lib/autoconf/c.m4
===================================================================
RCS file: /cvsroot/autoconf/autoconf/lib/autoconf/c.m4,v
retrieving revision 1.183
diff -p -u -r1.183 c.m4
--- lib/autoconf/c.m4   23 Sep 2003 23:05:11 -0000      1.183
+++ lib/autoconf/c.m4   15 Jan 2004 18:17:15 -0000
@@ -1,6 +1,6 @@
 # This file is part of Autoconf.                       -*- Autoconf -*-
 # Programming languages support.
-# Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
+# Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -824,10 +824,10 @@ static char *f (char * (*g) (char **, in
 /* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
    function prototypes and stuff, but not '\xHH' hex character constants.
    These don't provoke an error unfortunately, instead are silently treated
-   as 'x'.  The following induces an error, until -std1 is added to get
+   as 'x'.  The following induces an error, until -std is added to get
    proper ANSI mode.  Curiously '\x00'!='x' always comes out true, for an
    array size at least.  It's necessary to write '\x00'==0 to get something
-   that's true only with -std1.  */
+   that's true only with -std.  */
 int osf4_cc_array ['\x00' == 0 ? 1 : -1];
 
 int test (int i, double x);
@@ -840,11 +840,11 @@ char **argv;]],
 # Don't try gcc -ansi; that turns off useful extensions and
 # breaks some systems' header files.
 # AIX                  -qlanglvl=ansi
-# Ultrix and OSF/1     -std1
+# Ultrix, OSF/1, Tru64 -std
 # HP-UX 10.20 and later        -Ae
 # HP-UX older versions -Aa -D_HPUX_SOURCE
 # SVR4                 -Xc -D__EXTENSIONS__
-for ac_arg in "" -qlanglvl=ansi -std1 -Ae "-Aa -D_HPUX_SOURCE" "-Xc 
-D__EXTENSIONS__"
+for ac_arg in "" -qlanglvl=ansi -std -Ae "-Aa -D_HPUX_SOURCE" "-Xc 
-D__EXTENSIONS__"
 do
   CC="$ac_save_CC $ac_arg"
   _AC_COMPILE_IFELSE([],