2015-05-05  Jack Howarth  <howarth.at.gcc@gmail.com>

	* config.gcc: Use darwin9.h, darwin10.h and darwin12.h
	on darwin12 and later.
	* config/darwin12.h (LINK_GCC_C_SEQUENCE_SPEC): Add
	file to pass -rdynamic on darwin12 and later.
	* config/darwin.opt (rdynamic): Add.

From-SVN: r222822