obsolete: better error message if AM_PROG_CC_STDC is used

In Automake 1.13, the long-deprecated (since 2002) macro AM_PROG_CC_STDC
has been removed.  Such a removal, albeit sensible and justified, was
probably done in a too-abrupt way, since it didn't turn the pre-existing
warning messages into fatal error messages, but simply dropped the macro
definition, so that remaining usages of it would cause unclear error
messages, e.g.:

    configure.ac:4: warning: macro 'AM_PROG_CC_STDC' not found in library

from aclocal, and:

    configure.ac:4: error: possibly undefined macro: AM_PROG_CC_STDC
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.

from autoconf.

In an attempt to mitigate this issue, we re-add an AM_PROG_CC_STDC
definition that simply raises a *clear* error message when the macro
is used.

* t/am-prog-cc-stdc-no-more.sh: New test.
* t/list-of-tests.mk: Add it.
* m4/obsolete-err.m4: Add the new "error-raising" definition for
AM_PROG_CC_STDC; the error message is a variation of the one already
present in the older version of this macro, before it got removed in
commit 'v1.12-15-gd2ca168'.
* NEWS: Update.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

diff --git a/NEWS b/NEWS
index ce4a9c8..b135b2a 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -51,9 +51,9 @@ New in 1.13.1:
 
 * Bugs fixed:
 
-  - Use of the obsolete macro AM_CONFIG_HEADER causes a clear and
-    helpful error message, instead of obscure ones (issue introduced
-    in Automake 1.13).
+  - Use of the obsolete macros AM_CONFIG_HEADER or AM_PROG_CC_STDC now
+    causes a clear and helpful error message, instead of obscure ones
+    (issue introduced in Automake 1.13).
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

diff --git a/m4/obsolete-err.m4 b/m4/obsolete-err.m4
index 24321dd..2d7c518 100644 (file)
--- a/m4/obsolete-err.m4
+++ b/m4/obsolete-err.m4
@@ -12,6 +12,12 @@ AC_DEFUN([AM_CONFIG_HEADER],
 [AC_FATAL(['$0': this macro is obsolete.
     You should use the 'AC][_CONFIG_HEADERS' macro instead.])])
 
+AU_DEFUN([AM_PROG_CC_STDC],
+[AC_FATAL(['$0': this macro is obsolete.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])

diff --git a/t/am-prog-cc-stdc-no-more.sh b/t/am-prog-cc-stdc-no-more.sh
new file mode 100755 (executable)
index 0000000..268a4bf
--- /dev/null
+++ b/t/am-prog-cc-stdc-no-more.sh
@@ -0,0 +1,43 @@
+#! /bin/sh
+# Copyright (C) 2011-2012 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/>.
+
+# Check that any attempt to use the obsolete macro AM_CONFIG_HEADER
+# elicits clear and explicit fatal errors.
+
+. test-init.sh
+
+geterr ()
+{
+    "$@" -Wnone 2>stderr && { cat stderr >&2; exit 1; }
+    cat stderr >&2
+    grep "^configure\.ac:4:.*'AM_PROG_CC_STDC'.*obsolete" stderr
+    grep "'AC_PROG_CC'.* instead" stderr
+}
+
+$ACLOCAL
+mv aclocal.m4 aclocal.sav
+
+echo AM_PROG_CC_STDC >> configure.ac
+
+geterr $ACLOCAL
+test ! -f aclocal.m4
+
+cat aclocal.sav "$am_automake_acdir"/obsolete-err.m4 > aclocal.m4
+
+geterr $AUTOCONF
+geterr $AUTOMAKE
+
+:

diff --git a/t/list-of-tests.mk b/t/list-of-tests.mk
index 00162a8..4fe8216 100644 (file)
--- a/t/list-of-tests.mk
+++ b/t/list-of-tests.mk
@@ -132,6 +132,7 @@ t/amhello-binpkg.sh \
 t/aminit-moreargs-deprecation.sh \
 t/amassign.sh \
 t/am-config-header-no-more.sh \
+t/am-prog-cc-stdc-no-more.sh \
 t/am-macro-not-found.sh \
 t/amopt.sh \
 t/amopts-location.sh \