[Ada] Handling up-level references in loops within library-level declarations

[Ada] Handling up-level references in loops within library-level declarations

2019-10-10  Gary Dismukes  <dismukes@adacore.com>

gcc/ada/

	* exp_ch7.adb (Check_Unnesting_In_Decls_Or_Stmts): When
	encountering a loop at the top level of a package declaration
	list (that is, within the declarations of a package spec or
	body) that has nested subprograms, call Unnest_Loop to create a
	new library-level procedure that will contain the loop, to allow
	for proper handling of up-level references from within nested
	subprograms, such as to loop parameters.
	(Unnest_Loop): New procedure that takes a loop statement and
	creates a new procedure body to enclose the loop statement,
	along with generating a call to the procedure.

From-SVN: r276836