[libstdc++] minor fixes and improvements to check-abi

[Matthias Klose]

Phil Edwards writes:
> Fixes a minor shell syntax bug.  Sets up a default baseline file and allows
> overrides from configure.target.  Gives more informative messages in common
> or possibly-common check-abi mistakes.
> 
> I'm slightly confused why cross-targets would have been broken by the
> configury changes.  GLIBCPP_CONFIGURE_TESTSUITE now contains a test for
> native builds, but GLIBCPP_CONFIGURE_TESTSUITE itself is only run in the
> native build case.
> 
> Tested on i686-pc-linux-gnu... well, sortof.  (Followup on /that/ in
> a moment.)  Applied to trunk.  If this is all good after a day, I'll
> copy it to the branch.

How should the comparision with i386-pc-linux-gnu be handled? Debian
still uses this (i386-linux as alias).

> 2002-08-23  Phil Edwards  <pme@gcc.gnu.org>
> 
> 	* Makefile.am (check-abi):  Specify current directory.
> 	* acinclude.m4 (GLIBCPP_CONFIGURE_TESTSUITE):  Fix shell syntax, use
> 	abi_baseline_triplet in baseline_file.
> 	* Makefile.in, aclocal.m4, configure:  Regenerate.
> 	* configure.target:  Add abi_baseline_triplet with default.
> 	* testsuite/abi_check.cc:  More error checking.

thanks for the quick fixes

	Matthias