[arm] Use cl_target_options for configuring the active target

[arm] Use cl_target_options for configuring the active target

It now becomes apparent that it would be better to use the the
cl_target_options as the basis for calling arm_configure_build_target;
it already contains exactly the same fields that we need.  I chose not
to rewrite the earlier patches as that would make the progression of
changes seem less logical than it currently is, with several early
changes having no immediate justification.

	* arm-protos.h (arm_configure_build_target): Change second argument
	to cl_target_options.
	* arm.c (arm_configure_build_target): Likewise.
	(arm_option_restore): Update accordingly.
	(arm_option_override): Create the target_option_default_node before
	calling arm_configure_build_target.  Use it in call of latter.
	Resynchronize after all other overrides have been calculated.
	(arm_valid_target_attribute_tree): Use the target options for
	reconfiguration.  Resynchronize after performing override checks.
	* arm-c.c (arm_pragma_target_parse): Use target optiosn from cur_tree
	to reconfigure the build target.

From-SVN: r243713