Allow dejagnu to build without a working C++ compiler

[Nick Clifton]

Hi Guys,

  I have imported this patch from Savannah dejagnu repository into the
  sourceware repository:

    2002-08-30  Nick Clifton  <nickc@redhat.com>

        * acinclude.m4: Provide alternative definition of AC_PROG_CXX
        which does not call AC_PROG_CXX_WORKS.  This allows dejagnu to
        be configured and built without a working C++ compiler.

  I have not imported Rob's supplemental patch, which uses the
  AC_NO_EXECUTABLES macro, as this macro is not provided by autoconf
  version 2.13.

Cheers
        Nick