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.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@114845 138bc75d-0d04-0410-961f-82ee72b054a4