* configure.in: Reorganize handling of *-*-gnu*, to share target
	specific make details with Linux.  Update comments to clarify
        the distinction between GNU/Linux and GNU/Hurd.
	* config/t-gnu (LIBGCC1, CROSS_LIBGCC1, CRTSTUFF_T_CFLAGS,
	TARGET_LIBGCC2_CFLAGS): Remove.  We now use the settings from
	config/t-linux for the Hurd.

From-SVN: r37870