* config/s390/libgcc-libc.ver: Add multilib support.
	* config/s390/linux.h (MULTILIB_DEFAULT): Define.
	* config/s390/t-linux64 (MULTILIB_OPTIONS, MULTILIB_DIRNAMES,
	MULTILIB_OSDIRNAMES, LIBGCC, INSTALL_LIBGCC,
	EXTRA_MULTILIB_PARTS): Define.

From-SVN: r59342