Test __start_xxx/__stop_xxx symbol generation.
Fix a long-standing bug related to rebooting while a
reconstruct-to-spare is underway but not yet complete.

The issue was that a component was being marked as a used_spare when
the rebuild started, not when the rebuild was actually finished.
Marking it as a used_spare meant that the component label on the spare
was being updated such that after a reboot the component would be
considered up-to-date, regardless of whether the rebuild actually
completed!

This fix includes:
 1) Add an additional state "rf_ds_rebuilding_spare" which is used
    to denote that a spare is currently being rebuilt from the live
    components.
 2) Update the comments on the disk states, which were out-of-sync
    with reality.
 3) When rebuilding to a spare component, that spare now enters the
    state rf_ds_rebuilding_spare instead of the state rf_ds_used_spare.
 4) When the rebuild is actually complete then the spare component
    enters the rf_ds_used_spare state.  rf_ds_used_spare is now used
    exclusively for the case where the rebuilding to the spare has
    completed successfully.

XXX: Someday we need to teach raidctl(8) about this new state, and
take out the backwards compatibility code in rf_netbsdkintf.c (see
RAIDFRAME_GET_INFO in raidioctl()).  For today, this fix needs to be
generic enough that it can get backported without major grief.

XXX: Needs pullup to netbsd-5*, netbsd-6*, and netbsd-7

Fixes PR#49244.
Fix build with clang.
Adjust comment to reflect reality.  (5th arg, not 4th)
Define copysignl on !long double platforms. Be consistent in the use of
weak aliases.
LLVM switched to three component point release version, so follow here.
Install cpuid.h on X86 and arm_neon.h on ARM.
Fix thinko in previous.
Test orphan ELF section placement.
Tweak previous.
Commit to returning 1, not any nonzero value.
Do not uselessly include <sys/malloc.h>.
Allow the DEBE layer and output sizes to be set independently. Now you can
pass fb.margin=<n> in bootargs to add a border to the framebuffer, in case
your display doesn't let you turn off overscan and you really want to see
the whole screen.
bump year
Implement WSDISPLAYIO_SVIDEO, WSDISPLAYIO_GVIDEO for screen blanking
Drop pointer checks that are always true.
Comment out impossible code.
Remove tautologic check.
Skip vendor if the string is empty.
Use l_wmesg if the string is not empty. Don't bother checking l_name for
nullness.