[PR c++/84973] don't defer output of uninstantiated templates

[PR c++/84973] don't defer output of uninstantiated templates

When an anon struct gets a name through a typedef, we reset its
linkage and that of its members.  Member functions may get vague
linkage, which schedules them for deferred output, but we don't want
to add them to the queue if they're uninstantiated templates,
e.g. because the enclosing function is a template.  They will be added
as needed when the enclosing template is instantiated.

for  gcc/cp/ChangeLog

	PR c++/84973
	* decl2.c (note_vague_linkage_fn): Don't defer uninstantiated
	templates.

for  gcc/testsuite/ChangeLog

	PR c++/84973
	* g++.dg/template/pr84973.C: New.
	* g++.dg/template/pr84973-2.C: New.
	* g++.dg/template/pr84973-3.C: New.

From-SVN: r258914