opt.ads (Old_Checksums, [...]): New Boolean flags, defaulted to False.

opt.ads (Old_Checksums, [...]): New Boolean flags, defaulted to False.

2010-10-26  Vincent Celier  <celier@adacore.com>

	* opt.ads (Old_Checksums, Old_Old_Checksums): New Boolean flags,
	defaulted to False.
	* prj-nmsc.adb (Process_Project_Level_Array_Attributes): When
	processing attribute Toolchain_Version ("Ada"), set Opt.Old_Checksums
	and Opt.Old_Old_Checksums depending on the GNAT version.
	* scng.adb (Accumulate_Token_Checksum_Old): New procedure.
	(Accumulate_Token_Checksum_Old_Old): New procedure.
	(Scan): For keywords, when Opt.Old_Checksums is True, call one of the
	alternative procedures Accumulate_Token_Checksum_Old or
	Accumulate_Token_Checksum_Old_Old, instead of Accumulate_Token_Checksum.

From-SVN: r165959