PR c++/41109
PR c++/41110
PR c++/41134
* cp-tree.h (DECL_ODR_USED): New macro.
(struct lang_decl_base): Add odr_used flag.
* decl.c (duplicate_decls): Propagate it. Use it for error.
* pt.c (register_specialization): Use it for error.
* decl2.c (mark_used): Use it as gating flag rather than TREE_USED.
(cp_write_global_declarations): Use it for error.
(tree_used_ok): Remove.
* cp-tree.h: Remove tree_used_ok.
* call.c (build_call_a): Don't call it.
* init.c (build_offset_ref): Likewise.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@151061 138bc75d-0d04-0410-961f-82ee72b054a4