* cse.c (cse_main): Converts ifdefs on PIC_OFFSET_TABLE_REGNUM to
	conditionals.
	* defaults.h (PIC_OFFSET_TABLE_REGNUM): Default to INVALID_REGNUM.
	* emit-rtl.c (init_emit_once): Convert ifdefs to conditionals.
	* flow.c (mark_regs_live_at_end): Likewise.
	(calculate_global_regs_live): Likewise.
	* gcse.c (compute_hash_table): Likewise.
	(compute_kill_rd): Likewise.
	* resource.c (mark_target_live_regs): Likewise.
	* rtl.h (INVALID_REGNUM): New macro.

From-SVN: r39643