Changes for k*bsd-gnu support.

	* config/i386/linux.h: Define REG_NAME to allow overriding of
	register names in sc structure.
	* config/i386/linux-unwind.h: Refer to sc->REG_NAME(reg) instead
	of sc->reg.
	* config.gcc: Detect x86_64-k*bsd-gnu systems.

From-SVN: r91350