re PR target/40125 (libgcc_s DLL installed in wrong directory in cross toolchain)

gcc/ChangeLog:

	PR target/40125
	* config.gcc (i[34567]86-*-pe | i[34567]86-*-cygwin*): Select suitable
	t-dlldir{,-x} fragment for build and add it to tmake_file.
	(i[34567]86-*-mingw* | x86_64-*-mingw*): Likewise.
	* Makefile.in (libgcc.mvars): Also export SHLIB_DLLDIR to libgcc.
	* config/i386/t-dlldir: New file.
	(SHLIB_DLLDIR): Define.
	* config/i386/t-dlldir-x: New file.
	(SHLIB_DLLDIR): Define.
	* config/i386/t-cygming: Error out if SHLIB_DLLDIR is not set.
	(SHLIB_INSTALL): Use it.

libgcc/ChangeLog:

	PR target/40125
	* configure.ac: Call ACX_NONCANONICAL_TARGET.
	(toolexecdir): Calculate and AC_SUBST.
	(toolexeclibdir): Likewise.
	* Makefile.in (target_noncanonical): Import.
	(toolexecdir): Likewise.
	(toolexeclibdir): Likewise.
	* configure: Regenerate.

From-SVN: r169274