[Ada] Put_Image attribute

[Ada] Put_Image attribute

2020-06-11  Bob Duff  <duff@adacore.com>

gcc/ada/

	* exp_put_image.adb (Build_Record_Put_Image_Procedure): Remove
	special processing of protected types, because those are handled
	by Build_Protected_Put_Image_Call.
	(Enable_Put_Image): Use the switch -gnatd_z to control enabling
	of Put_Image. Disable Put_Image for types in Remote_Types
	packages.
	* debug.adb: Document -gnatd_z switch.
	* exp_imgv.adb, libgnat/a-stteou.ads, opt.ads: Minor cleanups.