c4x.c: Include system.h.

	* config/c4x/c4x.c: Include system.h.
 	(c4x_caller_save_map): Disable caller save for RC.
	(c4x_optimization_options): Disable scheduling before reload.
	(valid_parallel_load_store) : Define return type as int.
	Remove unused variable regs.
	* config/c4x/c4x.h (REGISTER_MOVE_COST): Make independent of register
	class.
	* config/c4x/c4x.md (rotlqi3, rotrqi3): Fix up emitted RTL to
	handle rotations.
	(*db, decrement_and_branch_until_zero): Fix up constraints
	to keep reload happy.

From-SVN: r24600