re PR target/17317 (Match Constraints for *movdf_insn fails)

re PR target/17317 (Match Constraints for *movdf_insn fails)

    gcc/ada/
	PR ada/17317
	* par-ch4.adb (Is_Parameterless_Attribute): New map.
	(P_Name, Scan_Apostrophe block): Parse left parenthesis following
	attribute name or not depending on the new map.

	* sem-attr.adb (Analyze_Attribute): Parameterless attributes
	returning a string or a type will not be called with improper
	arguments.

	* sem-attr.ads (Attribute_Class_Array): Move to snames.ads.

	* snames.ads (Attribute_Class_Array): Moved from sem-attr.ads.

    gcc/testsuite/
	PR ada/17317
	* gnat.dg/specs/attribute_parsing.ads: New test.

From-SVN: r130496