re PR c/19031 (#pragma weak handling changes in 4.0.0)

re PR c/19031 (#pragma weak handling changes in 4.0.0)

        PR c/19031
        * c-decl.c (pop_file_scope): Call maybe_apply_pending_pragma_weaks.
        * c-lang.c (finish_file): Don't do it here.
        * objc/objc-act.c (objc_finish_file): Likewise.

        * cgraph.c (decl_assembler_name_equal): New.
        (cgraph_node_for_asm, cgraph_varpool_node_for_asm): New.
        (cgraph_varpool_node): Actually link up cgraph_varpool_nodes.
        * cgraph.h (struct cgraph_varpool_node): Add next.
        (cgraph_node_for_asm, cgraph_varpool_node_for_asm): Declare.
        * varasm.c (assemble_alias): Mark the target as needed.

From-SVN: r92803