[Ada] Spurious error on pragma Independent_Components

[Ada] Spurious error on pragma Independent_Components

This patch modifies the analysis of pragma Independent_Components to account
for a side effect from handling of self-referential records which render the
pragma illegal.

------------
-- Source --
------------

--  pack.ads

package Pack is
   type OK is record
      Comp_1 : Integer;
      Comp_2 : access OK;
   end record;
   pragma Independent_Components (OK);

   type Error;
   pragma Independent_Components (Error);
   type Error is record
      Comp : Integer;
   end record;
end Pack;

----------------------------
-- Compilation and output --
----------------------------

$ gcc -c pack.ads
pack.ads:9:04: representation item must be after full type declaration

2018-05-24  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* sem_prag.adb (Analyze_Pragma): Use the full view of an internally
	generated incomplete type.

From-SVN: r260649