g++.exp (g++_link_flags): Use gcc-set-multilib-library-path.

g++.exp (g++_link_flags): Use gcc-set-multilib-library-path.

	* lib/g++.exp (g++_link_flags): Use gcc-set-multilib-library-path.
	(g++_init): Make sure that CXXFLAGS is set.
	* lib/gcc-defs.exp (gcc-set-multilib-library-path): New function.
	* lib/gcc-dg.exp: Use gcc-set-multilib-library-path.
	* lib/gfortran.exp (gfortran_link_flags): Likewise.
	* lib/objc.exp (objc_init): Likewise.
	* lib/treelang.exp (treelang_init): Likewise.

From-SVN: r97076