gprep.adb: Implement -C switch to scan comments

gprep.adb: Implement -C switch to scan comments

2005-11-14  Robert Dewar  <dewar@adacore.com>
	    Vincent Celier  <celier@adacore.com>

	* gprep.adb: Implement -C switch to scan comments

	* scng.adb: Scan comment symbol separately if Replace_In_Comments set

	* scans.ads: Comment updates (including new use of Tok_Comment in
	preprocessing)

	* opt.ads: Add documentation for flags that are used by gprmake,
	currently and in the next version of gprmake.
	(Verbosity_Level): New variable
	Add Replace_In_Comments switch

	* vms_data.ads: Add VMS equivalent for new gnatmake switches -vl, -vm
	and -vm.
	Add /REPLACE_IN_COMMENTS for gnatprep -C switch

From-SVN: r106983