MFC r239959:

MFC r239959:

  Work around several warnings from clang in the xfs filesystem, when
  linking it statically into the kernel.  With our gcc in base there are
  no warnings, so also remove the WERROR= from the module makefile.

  Noted by:	Eir Nym <eirnym@gmail.com>

MFC r240011:

  Partially revert r239959, after actually fixing most of the clang
  warnings in sys/gnu/fs/xfs.  The only warnings that still need to be
  suppressed are those about array bound overruns of flexible array
  members in xfs_dir2_{block,sf}.c, which are too expensive (in terms of
  cascading code changes) to fix.

git-svn-id: svn://svn.freebsd.org/base/stable/9@240207 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f