* resolve.cc (Symbol_table::resolve): Remember whether undef was

	* resolve.cc (Symbol_table::resolve): Remember whether undef was
	weak when resolving to a dynamic def.
	(Symbol_table::should_override): Add adjust_dyndef flag; set it
	for weak undef/dynamic def cases. Adjust callers.
	* symtab.cc (Symbol::init_fields): Initialize undef_binding_set_ and
	undef_binding_weak_.
	(Symbol_table::sized_write_globals): Adjust symbol binding.
	(Symbol_table::sized_write_symbol): Add binding parameter.
	* symtab.h (Symbol::set_undef_binding): New method.
	(Symbol::is_undef_binding_weak): New method.
	(Symbol::undef_binding_set_, Symbol::undef_binding_weak_): New members.
	(Symbol_table::should_override): Add new parameter.
	(Symbol_table::sized_write_symbol): Add new parameter.

	* testsuite/weak_undef_file1.cc: Add new test case.
	* testsuite/weak_undef_file2.cc: Fix header comment.
	* testsuite/weak_undef_test.cc: Add new test case.