rtsfind.ads: Add support for finding Super_String types.

rtsfind.ads: Add support for finding Super_String types.

2012-03-07  Bob Duff  <duff@adacore.com>

	* rtsfind.ads: Add support for finding Super_String types.
	* sem_util.ads, sem_util.adb (Is_Bounded_String): New function
	to determine whether a given type is a bounded string type.
	(Is_Fully_Initialized_Type): Return True for bounded
	string types, to suppress bogus warnings.
	* exp_ch4.adb (Expand_Composite_Equality): Special case for bounded
	strings: equality composes. This allows us to remove default values in
	super strings.
	* a-strsup.ads, a-stwisu.ads, a-stzsup.ads: Update comments.
	* exp_ch3.adb (Expand_Freeze_Record_Type): Comment.

From-SVN: r185066