another C++-related configuration fix for Bison

[Paul Eggert]

I installed this:

2006-02-09  Paul Eggert  <address@hidden>

        More portability fixes for problems summarized by Nelson H. F. Beebe.

        * m4/cxx.m4 (BISON_TEST_FOR_WORKING_CXX_COMPILER): Catch a
        configuration screwup "./configure CC=/opt/SUNWspro/bin/c89
        CFLAGS="-xarch=generic64" CXX=/opt/SUNWspro/bin/CC
        LDFLAGS="-xarch=generic64" with Sun C 5.7 on Solaris 10; this
        messes up because C++ code is compiled in 32-bit mode but linked
        in 64-bit mode.

Index: m4/cxx.m4
===================================================================
RCS file: /cvsroot/bison/bison/m4/cxx.m4,v
retrieving revision 1.7
diff -p -u -r1.7 cxx.m4
--- m4/cxx.m4   2 Feb 2006 23:53:07 -0000       1.7
+++ m4/cxx.m4   10 Feb 2006 07:52:16 -0000
@@ -25,7 +25,8 @@ AC_DEFUN([BISON_TEST_FOR_WORKING_CXX_COM
  AC_CACHE_CHECK([whether $CXX builds executables that work],
    bison_cv_cxx_works,
    [AC_LANG_PUSH([C++])
-    AC_RUN_IFELSE(
+    bison_cv_cxx_works=no
+    AC_COMPILE_IFELSE(
       [AC_LANG_PROGRAM(
         [#include <cstdlib>
          #include <iostream>
@@ -41,9 +42,12 @@ AC_DEFUN([BISON_TEST_FOR_WORKING_CXX_COM
          for (i = m.begin (); i != m.end (); ++i)
            if (i->first != 4)
              return 1;])],
-      [bison_cv_cxx_works=yes],
-      [bison_cv_cxx_works=no],
-      [bison_cv_cxx_works=cross])
+      [AS_IF([AC_TRY_COMMAND([$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS 
$LDFLAGS conftest.$ac_objext $LIBS >&AS_MESSAGE_LOG_FD])],
+        [AS_IF([test "$cross_compiling" = yes],
+           [bison_cv_cxx_works=cross],
+           [AS_IF([AC_TRY_COMMAND(./conftest$ac_exeext)],
+              [bison_cv_cxx_works=yes])])])
+       rm -f conftest$ac_exeext])
     AC_LANG_POP([C++])])
 
  case $bison_cv_cxx_works in