FreeBSD splits "zfs_context.h" into:
"lib/libzpool/common/sys/zfs_context.h" for user space
"uts/common/fs/zfs/sys/zfs_context.h" for kernel space
Do the same here, move and sync "sys/sys/zfs_context.h" to
"dist/lib/libzpool/common/sys/zfs_context.h" and
"dist/uts/common/fs/zfs/sys/zfs_context.h".
Change "Makefile.zfs" to search includes from "dist/lib"
before "dist/uts" so we get the right include file.
Adapt "usr.sbin/fstyp/Makefile" to get the right include file.
this changes the upstream vendor from OpenSolaris to FreeBSD,
and this version is based on FreeBSD svn r315983.
in addition to the 10 years of improvements from upstream,
this version also has these NetBSD-specific enhancements:
- dtrace FBT probes can now be placed in kernel modules.
- ZFS now supports mmap().