ansi-c++-opt fix

[Bruno Haible]

When using a gnulib testdir built with --with-c++-tests on HP-UX 11 aCC
or OSF/1 cxx, I get errors from 'depcomp':

  checking whether the C++ compiler (aCC -O  ) works... yes
  checking whether the C++ compiler supports namespaces... no
  checking dependency style of :... none
  ...
  source='test-math-c++.cc' object='test-math-c++.o' libtool=no \
  DEPDIR=.deps depmode=none /bin/sh ./../build-aux/depcomp \
  : -DHAVE_CONFIG_H -I.  -DGNULIB_STRICT_CHECKING=1 -I. -I. -I.. -I./.. 
-I../gllib -I./../gllib    -c -o test-math-c++.o test-math-c++.cc
  ./../build-aux/depcomp[611]: ::  not found.
  gmake[5]: *** [test-math-c++.o] Error 127

This fixes it.


2011-11-06  Bruno Haible  <address@hidden>

        ansi-c++-opt: Fix 2011-06-05 change.
        * m4/ansi-c++.m4 (gl_PROG_ANSI_CXX): When a C++ compiler is found but
        does not support namespaces, set the variable to "no", not to ":".

--- m4/ansi-c++.m4.orig Sun Nov  6 22:20:01 2011
+++ m4/ansi-c++.m4      Sun Nov  6 22:16:14 2011
@@ -1,4 +1,4 @@
-# ansi-c++.m4 serial 8
+# ansi-c++.m4 serial 9
 dnl Copyright (C) 2002-2003, 2005, 2010-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -84,7 +84,7 @@
     AC_LANG_POP([C++])
     AC_MSG_RESULT([$gl_cv_prog_ansicxx_works])
     if test $gl_cv_prog_ansicxx_works = no; then
-      CXX=:
+      CXX=no
     else
       dnl Test for namespaces.
       dnl We don't bother supporting pre-ANSI-C++ compilers.
@@ -105,7 +105,7 @@
       AC_LANG_POP([C++])
       AC_MSG_RESULT([$gl_cv_prog_ansicxx_namespaces])
       if test $gl_cv_prog_ansicxx_namespaces = no; then
-        CXX=:
+        CXX=no
       fi
     fi
   fi
-- 
In memoriam Louis Philippe d'Orléans 
<http://en.wikipedia.org/wiki/Louis_Philippe_II,_Duke_of_Orléans>