* Makefile.in: Pass a new MULTILIB_EXCLUSIONS option as the sixth
argument to genmultilib.
* genmultilib: accept new MULTILIB_EXCLUSIONS option and output
the contents into the multilib.h header.
* gcc.c: Declare multilib_exclusions for the specs file.
(set_multilib_dir): Use it.
(print_multilib_info): Likewise.
* t-linux64: Declare arguments for new MULTILIB_EXCLUSIONS option
to pass to genmultilib.
From-SVN: r32365
