* configure (gxx_include_dir): Removed.
	* configure.in (gxx_include_dir): Handle it.
	* Makefile.in: Likewise.
	* libio/configure.in (gxx_include_dir): Handle it.
	* libio/Makefile.in: Likewise.
	* libstdc++/configure.in (gxx_include_dir): Handle it.
	* libstdc++/Makefile.in: Likewise.

From-SVN: r26126