* configure.in (mips64r5900-sky-elf*): Use config/mt-sky.

	* configure.in (mips64r5900-sky-elf*): Use config/mt-sky.
	Set extraconfigdirs to build dvp-elf-as.
	* configure (extraconfigdirs): New variable.
	(SUBDIRS): Add extraconfigdirs and recurse on them too.
	* Makefile.in (all): Move higher in file.
	(EXTRA_TARGET_HOST_ALL_MODULES): New variable.
	(EXTRA_TARGET_HOST_{INSTALL,CHECK}_MODULES): New variables.
	(ALL_MODULES): Add EXTRA_TARGET_HOST_ALL_MODULES.
	(CROSS_CHECK_MODULES): Add EXTRA_TARGET_HOST_CHECK_MODULES.
	(INSTALL_MODULES): Add EXTRA_TARGET_HOST_INSTALL_MODULES.