Add SERDES support from Matthias Drochner. Not all devices were tested but all
SERDES entries are enabled.
restore the right colour map when X exits
Enable KMEM_REDZONE on DIAGNOSTIC. It will try to catch overflows.

No comment on tech-kern@
1) On 64bit systems, don't add the 32bit execsw[] to the global exec array.
   exec_elf32 works on 32bit systems only, and will crash 32bit binaries on
   64bit systems.
2) Now that exec_elf32 is dormant, we can give the native ELF loaders the
   highest priority.

Binaries will load faster now (system boot, compilation, etc.).

With the help of njloy@. Discussed a bit on tech-kern@, no disagreement.
Don't use scratch registers for X and to restore A after BPF_COPX call.
Two tweaks: don't use a temporary register to dereference the err agrument
after xcall and don't generate ((tmp1 & 0xf) << 2) twice in emit_msh().
Fix MODULE() dependencies to account for VND_COMPRESSION
Fix ttm swap storage destruction.
Do not printf(foobar()).  Bad bad bad bad bad!
'file system' for consistency with documentation (instead of 'filesystem').
 Add workaround for PR#48451. Some BCM5717-5720 based systems get NMI on boot.
This problem doesn't occur when we don't use prefetchable memory in the APE
area. I don't know the reason...  The way to not to use prefetchable memory
was adviced by Riastradh. Tested with HP MicroServer Gen8.
Override CPUFLAGS for compiler cpu-specific options, instead of appening
to CFLAGS. This allows the user to define CPUFLAGS without breaking the
build.
Fix source lists for radeon dri modules.
Define SLJIT_CACHE_FLUSH() for mips.
Add parentheses around macro arguments.
Add sljitarch.h to cobalt and pmax.
Implement rumpcomp_sync_icache() hyprecall for mips and add
a barebone implementation if mips cache ops to librumpkern_sljit.
Cast to __syncicache() argument types.
Cast to sparc_cache_flush() argument types. This change makes it clear
thatr sparc_cache_flush() is defined by sljit (unlike other ports).
Free temporary segs on the way out of bus_dmamap_load_pglist.