DWARF: allow dynamic data member offsets for inheritance info

DWARF: allow dynamic data member offsets for inheritance info

An unintended effect of the recently introduced machinery to handle
dynamic data member offsets in variable-length records (when
-fgnat-encodings=minimal) prevented GCC from describing correctly
inheritance information for classes in C++, which is a regression.

This change rectifies this machinery in this case.

gcc/ChangeLog:

	* dwarf2out.c (add_data_member_location_attribute): Do not
	disable dynamic data member offsets descriptions for TREE_BINFO
	members.

From-SVN: r231883