PR c++/20206
	* decl.c (cxx_comdat_group): Put thunks for
	TARGET_USE_LOCAL_THUNK_ALIAS_P (function) functions into the same
	comdat group as the thunk target.

	* g++.dg/opt/thunk2.C: New test.
	* g++.dg/opt/covariant1.C: New test.

From-SVN: r95619