Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Merge illumos commit 13455:7205f7794835

1458 D compiler fails to generate error on sizeof() an undefined struct

Reference:
https://www.illumos.org/issues/1458

Tested by: Fabian Keil
MFC after: 3 weeks

This commit was generated by cvs2svn to compensate for changes in r178476,
which included commits to RCS files with non-trunk default branches.