[FFmpeg-user] Cannot build ffmpeg with vulkan support anymore

[Ferdi Scholten]

Wanted to build the newest ffmpeg from git today (sept 4 2023), but to 
my surprise configuring failed with the error message

     ERROR: vulkan requested but not found

However vulkan is installed and active on my system, searching in the 
config.log revealed that indeed vulkan was found, but the version was to 
old. The expected version was 1.3.255 but the installed version is: 
1.3.239 (from latest stable MESA 23.1.6)

This is however a problem, as this version has indeed been released (jun 
2023) by the Khronos group, but is not yet implemented anywhere except 
in the most bleeding edge vulkan sources. Even the oibaf ppa does not 
have it yet (it is on 1.3.250)

My last build from git (Aug 25 2023) went flawless so somewhere in 
between the needed vulkan version was updated. As there is no 
(relatively easy way) to get the needed vulkan drivers for my system, 
are there really changes made in ffmpeg to make this new (as yet 
unobtainable) vulkan version necessary? Or will building with the older 
version break things?