acinclude.m4 (GLIBCXX_EXPORT_INSTALL_INFO): When cross-compiling, put headers in $prefix/$target/include/c++.

	* acinclude.m4 (GLIBCXX_EXPORT_INSTALL_INFO): When
	cross-compiling, put headers in $prefix/$target/include/c++.
	* configure: Regenerated.

	* configure.ac: Set gcc_gxx_include_dir to $target/include/c++
	when cross-compiling.  Do not substitute libstdcxx_incdir.
	* configure: Regenerated.

From-SVN: r114845