Makefile.in (FLAGS_FOR_TARGET): New macro.

* Makefile.in (FLAGS_FOR_TARGET): New macro.
(GCC_FOR_TARGET): Use it.
(CC_FOR_TARGET, CXX_FOR_TARGET, CHILL_FOR_TARGET): Now defined...
* configure.in: ... here.
(FLAGS_FOR_TARGET): Define.  Add ld build dir to -L path.
(libstdcxx_flags): Define and append to CXX_FOR_TARGET.

From-SVN: r35306