* config.gcc (m68k-*-linux*): Add with_arch.  Add sysroot-suffix.h
	to tm_file.  Add m68k/t-floatlib, m68k/t-linux & m68k/t-mlibs to
	tmake_file.
	* config/m68k/t-linux: New.
	* doc/install.texi: Document m68k-*-linux is now multilibbed by
	default.

From-SVN: r137557