Correct timeout computation. Fixes kern/33740.
Initial com framework changes.  These changes bust *all* com consumers, but
follow-up commits shortly will fix many of them, so that i386, sparc, and
some evbmips ports at least work.
Adapt to new com framework.
Adapt to new com framework.  While here, make sure com only matches real com
devices.
Adapt to new com framework, converting aucom.c clone to use common com.c.
Make these autoconfig com rather than aucom.
Configure com devices by default rather than aucom.
Configure com instead of aucom.
Use com_aubus.c attachment for console instead of (removed) aucom.
Initial work for PowerPC-specific com(4) rewhack.  Compile tested, but I
lack hardware to test.  If someone wants to validate, would be appreciated.
(Compile tested for WALNUT, EXPLORA451, and EV64260 kernels.)
MACE com(4) driver attachment rewhack.  GENERIC_IP3x compiles.  No real
test though, as I lack SGI hardware.
Another com_mainbus.c.  There are a few more of them left...  Again, only
compile tested at this point.
Another com_mainbus.  Again, only compile tested.
ARC com(4) fixes.  Somehow a syntax error in com_multi.c escaped me, too.
Alpha com(4) ports.
Fix a type where comconsregs was defined twice, and comkgdregs was missing.
Thanks to simonb@ Doh!
Fix to make this work with cross-building.  (sys/endian.h should not be
#include'd if HAVE_NBTOOL_CONFIG_H is defined.)
com(4) attachment hacks.  Note that these aren't as clean as they could be,
particularly com_hpcio.c, which has a custom bus_space which could probably
be eliminated.  But _I_ don't have an hpcmips to test with.  The compile of
MPC303 works, but GENERIC fails due to an error in tx39clock.c, so I'm
_not_ testing it.  (But both files at least _compiled_.)
amiga com(4) rewhack.  i can't cross-compile this from Solaris due to

sh /home/garrett/netbsd/src/sys/arch/m68k/fpsp/asm2gas /home/garrett/netbsd/src
/sys/arch/m68k/fpsp/fpsp.h >fpsp.defs
sed:   # format canonicalization is an unrecognized command.
sed:   # operator conversion is an unrecognized command.
sed:   # operand conversion is an unrecognized command.
sed:   # Floating point literal conversion is an unrecognized command.

so I am not entirely sure it even compiles.  YMMV.
Fix order of arguments to COM_INIT_REGS macro.  Fixes console problems
on a Walnut.