illumos gate

The vgatext driver /illumos-gate/usr/src/uts/intel/io/vgatext/
currently depends on the agpmaster driver (misc/agpmaster)
via a "-dy" flag in the Makefile here:
http://src.illumos.org/source/xref/illumos-gate/usr/src/uts/intel/vgatext/Makefile#49
Now that we're building the AGP drivers outside of illumos-gate,
it would be convenient if we did not have this dependency, or
at least if it were a run-time rather than link-time dependency.

The vgatext driver has a feature whereby it can pass through
ioctl calls to the misc/agpmaster module associated with the
attached VGA display (when found on a PCI bus). Such calls
are supported via "odd" minor devices (See AGPMASTER_MINOR)
http://src.illumos.org/source/search?q=AGPMASTER_MINOR&project=illumos-gate
There are no device nodes for these vgatext minor devices,
so this vgatext feature appears to be dead code.

This feature request will replace the (dead code) support for
agpmaster pass-through from vgatext with some syslog
messages (so we'll know if a consumer ever shows up).

The (old) misc/drm module in illumos gate also calls into
misc/agpmaster, optionally creating minor devices under
whatever top-level device linked misc/drm (i.e. i916) for
the agpmaster device. This relationship continues in the
newer DRM code over in the gfx-drm gate. For now, the
old drm code is still there in illumos-gate, but once that
goes away, no consumers of misc/agpmaster will remain
in illumos-gate.