gdb: use AC_PROG_CC_STDC instead of AM_PROG_CC_STDC

`autoconf -Wall` notes that AM_PROG_CC_STDC is obsolete:
Fixes this autoconf warning:

    configure.ac:40: warning: 'AM_PROG_CC_STDC': this macro is obsolete.
    configure.ac:40: You should simply use the 'AC_PROG_CC' macro instead.
    configure.ac:40: Also, your code should no longer depend upon 'am_cv_prog_cc_stdc',
    configure.ac:40: but upon 'ac_cv_prog_cc_stdc'.
    aclocal.m4:770: AM_PROG_CC_STDC is expanded from...
    configure.ac:40: the top level

Since we build with a C++ compiler now, I don't think this is relevant.
If you look at the messages removed from gdbsupport/aclocal.m4, it says
that this functionality is now integrated in AC_PROG_CC, which we
already call.  So it might not even make a difference.

We had a local version of AM_PROG_CC_STDC, in gdb/acinclude.m4 (only
used by gdb/configure.ac), remove it.

gdb/ChangeLog:

	* acinclude.m4 (AM_PROG_CC_STDC): Remove.
	* configure: Re-generate.
	* configure.ac: Remove AM_PROG_CC_STDC.

gdbsupport/ChangeLog:

	* aclocal.m4: Re-generate.
	* configure: Re-generate.
	* configure.ac: Remove AM_PROG_CC_STDC.

Change-Id: Ic824393598805d4f78cda9d119f8af46096e9c73

Author: simark

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2020-10-31  Simon Marchi  <[email protected]>
+
+	* acinclude.m4 (AM_PROG_CC_STDC): Remove.
+	* configure: Re-generate.
+	* configure.ac: Remove AM_PROG_CC_STDC.
+
 2020-10-31  Simon Marchi  <[email protected]>
 
 	* configure.ac: Use AC_CANONICAL_{BUILD,HOST,TARGET} instead of

gdb/acinclude.m4

@@ -78,114 +78,6 @@ m4_include(ax_cxx_compile_stdcxx.m4)
 
 m4_include([../config/ax_pthread.m4])
 
-## ----------------------------------------- ##
-## ANSIfy the C compiler whenever possible.  ##
-## From Franc,ois Pinard                     ##
-## ----------------------------------------- ##
-
-# Copyright (C) 1996-2020 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
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, see <http://www.gnu.org/licenses/>.
-
-# serial 1
-
-# @defmac AC_PROG_CC_STDC
-# @maindex PROG_CC_STDC
-# @ovindex CC
-# If the C compiler in not in ANSI C mode by default, try to add an option
-# to output variable @code{CC} to make it so.  This macro tries various
-# options that select ANSI C on some system or another.  It considers the
-# compiler to be in ANSI C mode if it handles function prototypes correctly.
-#
-# If you use this macro, you should check after calling it whether the C
-# compiler has been set to accept ANSI C; if not, the shell variable
-# @code{am_cv_prog_cc_stdc} is set to @samp{no}.  If you wrote your source
-# code in ANSI C, you can make an un-ANSIfied copy of it by using the
-# program @code{ansi2knr}, which comes with Ghostscript.
-# @end defmac
-
-AC_DEFUN([AM_PROG_CC_STDC],
-[AC_REQUIRE([AC_PROG_CC])
-AC_BEFORE([$0], [AC_C_INLINE])
-AC_BEFORE([$0], [AC_C_CONST])
-dnl Force this before AC_PROG_CPP.  Some cpp's, eg on HPUX, require
-dnl a magic option to avoid problems with ANSI preprocessor commands
-dnl like #elif.
-dnl FIXME: can't do this because then AC_AIX won't work due to a
-dnl circular dependency.
-dnl AC_BEFORE([$0], [AC_PROG_CPP])
-AC_MSG_CHECKING([for ${CC-cc} option to accept ANSI C])
-AC_CACHE_VAL(am_cv_prog_cc_stdc,
-[am_cv_prog_cc_stdc=no
-ac_save_CC="$CC"
-# Don't try gcc -ansi; that turns off useful extensions and
-# breaks some systems' header files.
-# AIX			-qlanglvl=ansi
-# Ultrix and OSF/1	-std1
-# 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__"
-do
-  CC="$ac_save_CC $ac_arg"
-  AC_TRY_COMPILE(
-[#include <stdarg.h>
-#include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-/* Most of the following tests are stolen from RCS 5.7's src/conf.sh.  */
-struct buf { int x; };
-FILE * (*rcsopen) (struct buf *, struct stat *, int);
-static char *e (p, i)
-     char **p;
-     int i;
-{
-  return p[i];
-}
-static char *f (char * (*g) (char **, int), char **p, ...)
-{
-  char *s;
-  va_list v;
-  va_start (v,p);
-  s = g (p, va_arg (v,int));
-  va_end (v);
-  return s;
-}
-int test (int i, double x);
-struct s1 {int (*f) (int a);};
-struct s2 {int (*f) (double a);};
-int pairnames (int, char **, FILE *(*)(struct buf *, struct stat *, int), int, int);
-int argc;
-char **argv;
-], [
-return f (e, argv, 0) != argv[0]  ||  f (e, argv, 1) != argv[1];
-],
-[am_cv_prog_cc_stdc="$ac_arg"; break])
-done
-CC="$ac_save_CC"
-])
-if test -z "$am_cv_prog_cc_stdc"; then
-  AC_MSG_RESULT([none needed])
-else
-  AC_MSG_RESULT([$am_cv_prog_cc_stdc])
-fi
-case "x$am_cv_prog_cc_stdc" in
-  x|xno) ;;
-  *) CC="$CC $am_cv_prog_cc_stdc" ;;
-esac
-])
-
 dnl written by Guido Draheim <[email protected]>, original by Alexandre Oliva 
 dnl Version 1.3 (2001/03/02)
 dnl source http://www.gnu.org/software/ac-archive/Miscellaneous/ac_define_dir.html

gdb/configure

@@ -5024,88 +5024,6 @@ rm -rf conftest*
 fi
 
 
-
-
-
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ${CC-cc} option to accept ANSI C" >&5
-$as_echo_n "checking for ${CC-cc} option to accept ANSI C... " >&6; }
-if ${am_cv_prog_cc_stdc+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  am_cv_prog_cc_stdc=no
-ac_save_CC="$CC"
-# Don't try gcc -ansi; that turns off useful extensions and
-# breaks some systems' header files.
-# AIX			-qlanglvl=ansi
-# Ultrix and OSF/1	-std1
-# 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__"
-do
-  CC="$ac_save_CC $ac_arg"
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <stdarg.h>
-#include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-/* Most of the following tests are stolen from RCS 5.7's src/conf.sh.  */
-struct buf { int x; };
-FILE * (*rcsopen) (struct buf *, struct stat *, int);
-static char *e (p, i)
-     char **p;
-     int i;
-{
-  return p[i];
-}
-static char *f (char * (*g) (char **, int), char **p, ...)
-{
-  char *s;
-  va_list v;
-  va_start (v,p);
-  s = g (p, va_arg (v,int));
-  va_end (v);
-  return s;
-}
-int test (int i, double x);
-struct s1 {int (*f) (int a);};
-struct s2 {int (*f) (double a);};
-int pairnames (int, char **, FILE *(*)(struct buf *, struct stat *, int), int, int);
-int argc;
-char **argv;
-
-int
-main ()
-{
-
-return f (e, argv, 0) != argv[0]  ||  f (e, argv, 1) != argv[1];
-
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-  am_cv_prog_cc_stdc="$ac_arg"; break
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-done
-CC="$ac_save_CC"
-
-fi
-
-if test -z "$am_cv_prog_cc_stdc"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
-$as_echo "none needed" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $am_cv_prog_cc_stdc" >&5
-$as_echo "$am_cv_prog_cc_stdc" >&6; }
-fi
-case "x$am_cv_prog_cc_stdc" in
-  x|xno) ;;
-  *) CC="$CC $am_cv_prog_cc_stdc" ;;
-esac
-
 # Expand $ac_aux_dir to an absolute path.
 am_aux_dir=`cd "$ac_aux_dir" && pwd`
 

gdb/configure.ac

@@ -29,7 +29,6 @@ AC_PROG_CXX
 
 AC_USE_SYSTEM_EXTENSIONS
 ACX_LARGEFILE
-AM_PROG_CC_STDC
 AM_PROG_INSTALL_STRIP
 
 AC_CONFIG_AUX_DIR(..)

gdbsupport/ChangeLog

@@ -1,3 +1,9 @@
+2020-10-31  Simon Marchi  <[email protected]>
+
+	* aclocal.m4: Re-generate.
+	* configure: Re-generate.
+	* configure.ac: Remove AM_PROG_CC_STDC.
+
 2020-10-31  Simon Marchi  <[email protected]>
 
 	* configure.ac: Use AC_CANONICAL_{BUILD,HOST,TARGET} instead of

gdbsupport/aclocal.m4

@@ -751,35 +751,6 @@ else
 fi
 ])
 
-#  -*- Autoconf -*-
-# Obsolete and "removed" macros, that must however still report explicit
-# error messages when used, to smooth transition.
-#
-# Copyright (C) 1996-2017 Free Software Foundation, Inc.
-#
-# This file is free software; the Free Software Foundation
-# gives unlimited permission to copy and/or distribute it,
-# with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([AM_CONFIG_HEADER],
-[AC_DIAGNOSE([obsolete],
-['$0': this macro is obsolete.
-You should use the 'AC][_CONFIG_HEADERS' macro instead.])dnl
-AC_CONFIG_HEADERS($@)])
-
-AC_DEFUN([AM_PROG_CC_STDC],
-[AC_PROG_CC
-am_cv_prog_cc_stdc=$ac_cv_prog_cc_stdc
-AC_DIAGNOSE([obsolete],
-['$0': this macro is obsolete.
-You should simply use the 'AC][_PROG_CC' macro instead.
-Also, your code should no longer depend upon 'am_cv_prog_cc_stdc',
-but upon 'ac_cv_prog_cc_stdc'.])])
-
-AC_DEFUN([AM_C_PROTOTYPES],
-         [AC_FATAL([automatic de-ANSI-fication support has been removed])])
-AU_DEFUN([fp_C_PROTOTYPES], [AM_C_PROTOTYPES])
-
 # Helper functions for option handling.                     -*- Autoconf -*-
 
 # Copyright (C) 2001-2017 Free Software Foundation, Inc.