[C++ PATCH] anon type names

[C++ PATCH] anon type names

https://gcc.gnu.org/ml/gcc-patches/2019-10/msg01354.html
I noticed that we use a bitfield flag to note types with names for linkage
purposes:
  typedef struct {} foo;
but, we can infer this by comparing TYPE_STUB_DECL and TYPE_DECL of the
main variant.  It's only checked in two places -- the C++ parser
and the objective C++ encoder.
	* cp-tree.h (struct lang_type): Remove was_anonymous.
	(TYPE_WAS_UNNAMED): Implement by checking TYPE_DECL &
	TYPE_STUB_DECL.
	* decl.c (name_unnamed_type): Don't set TYPE_WAS_UNNAMED.

From-SVN: r277155