I would look over the updated GNV components, particularly the VMS specific source and build procedures.
https://sourceforge.net/projects/gnv/files/ Source repositories (Mercurial) are available at https://sourceforge.net/p/gnv/_list/hg?source=navbar .
The GNV updated modules like coreutils contain wrapper libraries that allow select() and poll() to work with X11.
There are some tricks needed for porting X11 applications to VMS. You will likely need a wrapper to the main() routine.
1. GNV Bash contains the code to set the DISPLAY environment variable that ported X11 programs expect to the VMS default DECWindows display device you created.
2. OpenVMS uses event flags instead of file descriptors for X11. It uses event flags from the free event flag pool. By default only 2 are free. Look those up in the documentation and use dup() to create file descriptors to /dev/null for them to prevent the the application from opening actual files using those file descriptor numbers.
Much of the older ports are assuming an older VMS version than 8.4.
malmberg August 04 2022 No more VAX hobbyist licenses.
Community licenses for Alpha/IA64/X86_64 VMS Software Inc.
Commercial VMS software licenses for VAX available from HPE.
ozboomer July 20 2022 Just re-visiting.. No more hobbyist licenses? Is that from vmssoftware.com, no 'community' licenses?
valdirfranco July 01 2022 No more hobbyist license...sad
mister_wavey February 12 2022 I recall that the disks failed on the public access VMS systems that included Fafner
parwezw January 03 2022 Anyone know what happened to FAFNER.DYNDS.ORG?
I had a hobbyist account here but can longer access the site.
gtackett October 27 2021 Make that DECdfs _2.1A_ for Vax
gtackett October 27 2021 I'm looking for DECdfs V2.4A kit for VAX.
Asking here just in case anyone is still listening.
MarkRLV September 17 2021 At one time, didn't this web site have a job board? I would love to use my legacy skills one last time in my career.
malmberg January 18 2021 New Hobbyist PAKs for VAX/VMS are no longer available according to reports. Only commercial licenses are reported to be for sale from HPE
dfilip January 16 2021 Can someone please point me to hobbyist license pak? I'm looking for VAX/VMS 7.1, DECnet Phase IV, and UCX/TCPIP ... have the 7.1 media, need the license paks ... thanks!