crash printing optimized out variant type

Assuming the following declarations:

   type Discriminants_Record (A : Integer; B : Boolean) is record
      C : Float;
   end record;
   Z : Discriminants_Record := (A => 1, B => False, C => 2.0);

If variable Z is not used, and the compiler optimizes it out,
GDB would crash as follow:

    (gdb) print Z
    /[...]/gdb/valops.c:1121: internal-error: Unexpected lazy value type.

This is because the ada-lang module forgot to set the optimized_out
flag in the value returned by ada_evaluate_subexp during the value's
"fixing" process.  Later on, when trying to print the resulting value,
GDB finds that the value is still lazily allocated, and thus tries to
fetch it. But this is not allowed for not_lval values, hence the internal
error.

gdb/ChangeLog:

        * ada-lang.c (coerce_unspec_val_to_type): Make sure that
        the optimized_out flag is preserved.

gdb/testsuite/ChangeLog:

        * gdb.ada/optim_drec: New testcase.

1 files changed, 1 insertions, 0 deletions

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index bba045b4ba3..f45815f7686 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -581,6 +581,7 @@ coerce_unspec_val_to_type (struct value *val, struct type *type)
       set_value_bitsize (result, value_bitsize (val));
       set_value_bitpos (result, value_bitpos (val));
       set_value_address (result, value_address (val));
+      set_value_optimized_out (result, value_optimized_out (val));
       return result;
     }
 }