TL;DR  Still hanging out for x86 native compiler(s) but there will be an
x86-64 distribution of WASD v12.1 when released.  V9.2 performance >2x.

In the meantime, continuing to build off-platform with VSI I64VMS X86_XTOOLS
V9.2-XG9N (courtesy Jeremy Begg and VSM Software Services), and while there
is the hassle of edit/compile/zip/xfer/unzip/link rather than just build, it
is manageable as long as you are developing (and/or debugging :-) on another
platform and not actually trying to do these under V9.2, which IMO currently
is test-bed only.

Fortunately, at least for application programming, and as previously
suggested, VMS is VMS is VMS is (largely) VMS ...

  https://wasd.vsm.com.au/other/VMS_VMS_VMS_VMS.pdf

WASD v12.1 is in the offing, and (waiting for native compilers) was untested
on V9.2.  So, updating VirtualBox (under Windows 10), recreating 16GB and
64GB virtual disks, installing V9.2 from ISO image -- as a familiar 1)
Upgrade, install or reconfigure OpenVMS X86-64 Version V9.2 -- applying
mandatory updates, configuring licences, and TCP/IP Services and OpenSSH, had
a working system.  Really is quicker and easier than it might sound.

|Device                  Device           Error   Volume          Free  Trans Mnt
| Name                   Status           Count    Label          Space Count Cnt
|X86VMS$DMM0:            Offline              0
|X86VMS$DKA0:            Mounted              0 X86SYS          13.86GB   216   1
|X86VMS$DKA100:          Mounted              0 RESOURCES       62.26GB    11   1
|X86VMS$DKA200:          Online wrtlck        0

Then, just a matter of placing a pre-release WASD1210.ZIP onto a scratch area
on the IA64 system and another onto the x86-64 system, top-level of RESOURCES
volume.  Ensuring @SYS$MANAGER:X86_XTOOLS$SYLOGIN.COM, then using
'@[.WASD_ROOT.SRC]BUILD_ALL DIST' on the IA64 system compile the source code,
then 'ZIP "-V" location:WASD1210_OBJ_X86.ZIP [...OBJ_X86_64]*.OBJ', transfer
to the X86 system, UNZIP in the [.WASD_ROOT.SRC] tree, and finally
'@[.WASD_ROOT.INSTALL]INSTALL.COM' with 'LINK' to build the X86 executable
code.

Having been through the initial x86-64 -specific coding during the WASD v12.0
development there were nothing of that ilk with v12.1.  Very much build,
configure, execute OWASP ZAP against it to make sure it didn't explode in
one's face.  It didn't.  Mostly.  Revealed a couple of quirks introduced in
v12.1 which were analysed and addressed.  Of course, V9.2 is very much a
work-in-progress, and this testing encountered a significant OS bug --

|MMG$PAGEFAULT IPLHI:
|VSI Dump Kernel SYSBOOT Jun 2 2022 11:43:57
|**** OpenVMS x86_64 Operating System V9.2 - BUGCHECK ****
|** Bugcheck code = 0000035C: PGFIPLHI, Pagefault with IPL too high 

-- twice -- but without being obviously reproducible.  Reported to VSI via
their online Service Platform and currently under investigation.

Bottom-line, there will be V9.2 x86-64 object code distributed with the v12.1
release.

Performance under V9.2, as measured by the same humble VUPS.COM on the same
AU$300.00 pre-loved desktop reported in the PDF above -- Dell Optiplex 9020,
Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz RAM 16.0 GB, Windows 10 Pro Version
22H2 Installed 17/03/2021, VirtualBox 6.1.40 -- has *** IMPROVED >2x *** and
now exceeds that of the VSM rx2660.

|innotek GmbH VirtualBox with 2 CPU and 7574MB running VMS V9.2
|INFO: Preventing endless loop (10$) on fast CPUs
|Approximate System VUPs Rating : 575.2 ( min: 572.0 max: 579.2 )

|HP rx2660 (1.40GHz/6.0MB) with 4 CPU and 14335MB running VMS V8.4-2L1
|INFO: Preventing endless loop (10$) on fast CPUs
|Approximate System VUPs Rating : 498.0 ( min: 491.4 max: 502.0 )

Some images attached to illustrate WASD running under V9.2.

Regards, Mark.

PS. The entire WASD x86 porting not-a-blog is available
    https://wasd.vsm.com.au/other/#WASD_x86-64