* config/aarch64/t-aarch64-linux (MULTARCH_DIRNAME): Remove.
	(MULTILIB_OSDIRNAMES): Set.
	* genmultilib: If defaultosdirname doesn't start with :: , set
	defaultosdirname2 instead, clear it and emit two . multilib_raw
	entries instead of just one.

From-SVN: r196649