* config/mmix/mmix-protos.h: Convert prototypes to ISO C90.
	* config/mmix/mmix.c: Convert functions to ISO C90.
  	(mmix_eh_return_handler_rtx, mmix_output_shifted_value): Tweak
	formatting.
	(mmix_get_hard_reg_initial_val): Tweak section head comment.

From-SVN: r69466