2017-11-16  Sylvain Dailler  <dailler@adacore.com>

	* sem_util.adb (Get_Enum_Lit_From_Pos): Add a condition for Pos
	lower than 0.

2017-11-16  Bob Duff  <duff@adacore.com>

	* sem_ch13.adb (Check_Expr_Constants): Avoid error message in case of
	System'To_Address.

From-SVN: r254818