Fix the zfsd build on sparc64

lib/libdevdctl/event.cc
cddl/usr.sbin/zfsd/case_file.cc
Remove C++11isms

cddl/usr.sbin/zfsd/vdev.cc
cddl/usr.sbin/zfsd/zfsd_event.cc
Undefine the flush macro, which is defined by cpufunc.h for sparc64
only. It conficts with std::[io]stream::flush

Sponsored by: Spectra Logic Corp