Merge commit 3fcd73747 from openzfs git (by Adrian Chadd):

Merge commit 3fcd73747 from openzfs git (by Adrian Chadd):

  Fix compiling on FreeBSD + gcc - don't assume illmnos bits

  This looks like it was once from the illumnos compat code.
  FreeBSD doesn't have cmn_err as a compiler format attribute, so
  it definitely errors out.

  It doesn't show up on LLVM because it doesn't trigger at all.

  Add in the format flags but keep them behind #if 0 for now;
  there are too many format issues that trigger when one does
  format checking in the shared code.

  Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
  Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
  Signed-off-by: adrian chadd <adrian@freebsd.org>
  Closes #11068
  Closes #11069