bison configure --enable-gcc-warnings patch for C++ tests

[Paul Eggert]

I was getting failures like this when I tested Bison with
--enable-gcc-warnings and GCC 3.3:

   $ ./testsuite -v -d 80
   ## ---------------------------- ##
   ## GNU Bison 1.875b test suite. ##
   ## ---------------------------- ##
   80. calc.at:615: testing Calculator %skeleton lalr1.cc %defines %locations...
   calc.at:615: bison -o calc.c calc.y
   calc.at:615: $CXX --version || exit 77
   stderr:
   stdout:
   g++ (GCC) 3.3
   Copyright (C) 2003 Free Software Foundation, Inc.
   This is free software; see the source for copying conditions.  There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

   calc.at:615: $CXX $CFLAGS $CPPFLAGS calc.c -o calc
   stderr:
   cc1plus: warning: "-Wbad-function-cast" is valid for C/ObjC but not for C++
   cc1plus: warning: "-Wmissing-declarations" is valid for C/ObjC but not for 
C++
   cc1plus: warning: "-Wnested-externs" is valid for C/ObjC but not for C++

The problem is that C-only warning options are passed to the C++ compiler.
I installed the following patch.

2003-06-01  Paul Eggert  <address@hidden>

        Don't pass C-only warning optins (e.g., -Wmissing-declarations)
        to g++, as GCC 3.3 complains if you do it.
        * configure.ac (WARNING_CXXFLAGS): New subst.  Set it to
        everything that WARNING_CFLAGS has, except omit warnings
        not suitable for C++.
        (AC_PROG_CXX): Use this instead of AC_CHECK_PROGS([CXX], [g++]).
        * tests/atlocal.in (CXXFLAGS): New var.
        * tests/local.at (AT_COMPILE_CXX): Use it instead of CFLAGS.

Index: configure.ac
===================================================================
RCS file: /cvsroot/bison/bison/configure.ac,v
retrieving revision 1.35
diff -p -u -r1.35 configure.ac
--- configure.ac        27 Apr 2003 05:27:15 -0000      1.35
+++ configure.ac        2 Jun 2003 06:51:20 -0000
@@ -46,16 +46,18 @@ if test "${enableval}" = yes; then
   WARNING_CFLAGS=
   BISON_WARNING(-Wall)
   BISON_WARNING(-W)
-  BISON_WARNING(-Wbad-function-cast)
   BISON_WARNING(-Wcast-align)
   BISON_WARNING(-Wcast-qual)
   BISON_WARNING(-Wformat)
-  BISON_WARNING(-Wmissing-declarations)
   BISON_WARNING(-Wmissing-prototypes)
-  BISON_WARNING(-Wnested-externs)
   BISON_WARNING(-Wshadow)
   BISON_WARNING(-Wstrict-prototypes)
   BISON_WARNING(-Wwrite-strings)
+  AC_SUBST([WARNING_CXXFLAGS], [$WARNING_CFLAGS])
+  # The following warnings are not suitable for C++.
+  BISON_WARNING(-Wbad-function-cast)
+  BISON_WARNING(-Wmissing-declarations)
+  BISON_WARNING(-Wnested-externs)
   AC_DEFINE([lint], 1, [Define to 1 if the compiler is checking for lint.])
 fi
 
@@ -132,7 +134,7 @@ AC_CONFIG_TESTDIR(tests)
 AC_CONFIG_FILES([tests/Makefile tests/atlocal])
 AC_CONFIG_FILES([tests/bison], [chmod +x tests/bison])
 AC_CHECK_PROGS([VALGRIND], [valgrind])
-AC_CHECK_PROGS([CXX], [g++])
+AC_PROG_CXX
 AM_MISSING_PROG([AUTOM4TE], [autom4te])
 # Needed by tests/atlocal.in.
 AC_SUBST([GCC])
Index: tests/atlocal.in
===================================================================
RCS file: /cvsroot/bison/bison/tests/atlocal.in,v
retrieving revision 1.13
diff -p -u -r1.13 atlocal.in
--- tests/atlocal.in    18 Feb 2003 05:08:55 -0000      1.13
+++ tests/atlocal.in    2 Jun 2003 06:51:20 -0000
@@ -17,6 +17,9 @@ GCC='@GCC@'
 # The GCC C++ compiler.
 CXX='@CXX@'
 
+# We want no optimization with C++, too.
+CXXFLAGS='@O0CFLAGS@ @WARNING_CXXFLAGS@ @WERROR_CFLAGS@'
+
 # Are special link options needed?
 LDFLAGS='@LDFLAGS@'
 
Index: tests/local.at
===================================================================
RCS file: /cvsroot/bison/bison/tests/local.at,v
retrieving revision 1.1
diff -p -u -r1.1 local.at
--- tests/local.at      2 Mar 2003 11:14:07 -0000       1.1
+++ tests/local.at      2 Jun 2003 06:51:20 -0000
@@ -176,7 +176,7 @@ m4_define([AT_COMPILE],
 m4_define([AT_COMPILE_CXX],
 [AT_KEYWORDS(c++)
 AT_CHECK([$CXX --version || exit 77], 0, ignore, ignore)
-AT_CHECK([$CXX $CFLAGS $CPPFLAGS m4_default([$2], [$1.c]) -o $1],
+AT_CHECK([$CXX $CXXFLAGS $CPPFLAGS m4_default([$2], [$1.c]) -o $1],
          0, [], [ignore])])