Ignore config/compile, it's generated by automake.
Comment out namedstream methods.

These don't link properly; though they exist in sys/vnode_if.h on OS X.
Log and require all autogen commands to succeed.
Improvements for zfs.kext build & install targets.

Link in spl.kext directly, as if it's discovered via @SPL@ being a already
built spl source tree.  Add extensions to the linking.  This fixes the link
stage so there are no more warnings.

Add a new target, debug-kext-linking, which is useful for making kextlibs
describe in more detail linking problems.

Implement the install target.
Update for newer autoconf/automake.