PR c++/77337 - auto return and lambda
* pt.c (tsubst_friend_function): Don't set DECL_INITIAL.
(instantiate_decl): It's OK to defer a constexpr function.
* cp-tree.h (DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION): Check
DECL_LANG_SPECIFIC.
* decl2.c (decl_defined_p): Use it. No longer static.
* decl.c (redeclaration_error_message): Use decl_defined_p.
* constexpr.c (cxx_eval_call_expression): Set input_location around
call to instantiate_decl.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@242056 138bc75d-0d04-0410-961f-82ee72b054a4