This patch modifies the set of attributes that applies to entries and
entry families to include elaboration entities used by the
access-before-elaboration mechanism.

2018-08-21  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* einfo.adb (Elaboration_Entity): Include entries and entry
	families in the set of legal entities.
	(Elaboration_Entity_Required): Include entries and entry
	families in the set of legal entities.
	(Set_Elaboration_Entity): Include entries and entry families in
	the set of legal entities.
	(Set_Elaboration_Entity_Required): Include entries and entry
	families in the set of legal entities.
	(Write_Field13_Name): Update the output of attribute
	Elaboration_Entity.
	* einfo.ads: Attributes Elaboration_Entity and
	Elaboration_Entity_Required now apply to entries and entry
	families.

gcc/testsuite/

	* gnat.dg/elab6.adb, gnat.dg/elab6.ads, gnat.dg/elab6_pkg.adb,
	gnat.dg/elab6_pkg.ads: New testcase.

From-SVN: r263712