[Ada] New restriction No_Tagged_Type_Registration

gcc/ada/

	* libgnat/s-rident.ads (No_Tagged_Type_Registration): New
	restriction identifier.
	* restrict.ads (Implementation_Restriction): Add restriction.
	* exp_ch7.adb (Process_Declarations): Suppress
	tagged-type-related finalization actions if the restriction is
	active.  Call RTE_Available last.
	* exp_disp.adb (Make_DT): Likewise.
	* exp_util.adb (Requires_Cleanup_Actions): Return False for a
	tagged type declaration if No_Tagged_Type_Registration is
	active.
	* sem_attr.adb (Check_Stream_Attribute): Check restriction
	No_Tagged_Type_Registration.
	* libgnat/a-except.ads (Null_Occurrence): Minor: Initialize, to
	avoid stopping at a warning in gdb.
	* doc/gnat_rm/standard_and_implementation_defined_restrictions.rst:
	Document new restriction.
	* gnat_rm.texi: Regenerate.

1 files changed, 5 insertions, 3 deletions

diff --git a/gcc/ada/libgnat/a-except.ads b/gcc/ada/libgnat/a-except.ads
index b6c8bb5..0258d0e 100644
--- a/gcc/ada/libgnat/a-except.ads
+++ b/gcc/ada/libgnat/a-except.ads
@@ -286,8 +286,10 @@ private
    pragma Stream_Convert (Exception_Occurrence, String_To_EO, EO_To_String);
    --  Functions for implementing Exception_Occurrence stream attributes
 
-   pragma Warnings (Off, "aggregate not fully initialized");
-   Null_Occurrence : constant Exception_Occurrence := (others => <>);
-   pragma Warnings (On, "aggregate not fully initialized");
+   Null_Occurrence : constant Exception_Occurrence :=
+     (Machine_Occurrence => System.Null_Address,
+      Msg => (others => '*'),
+      Tracebacks => (others => System.Traceback_Entries.Null_TB_Entry),
+      others => <>);
 
 end Ada.Exceptions;