This is pretty dubious. I think it works around some old omission but it may well mess things up now.
Fixed these two. Bit odd that I’ve never seen them, also using Ubuntu 18.04 on some of the deployment machines. Anyway, both warnings are harmless.
This is rather odd. Building the package docs depends on the prolog_home target which builds the home directory in the binary dir. Just running ninja prolog_home on a freshly configured system does create a home with these files. I’ve build the system with a quite different number of cores (changes timing), both using ninja and make and ranging from fully sequential to 32 cores. Didn’t find any issues.
Also tried another common trick: remove one of the dependencies of a target and build the target. If the dependency isn’t properly declared this will fail. But this works fine:
rm home/xpce/prolog/lib/swi_hooks.pl
ninja packages/cpp/pl2cpp.tex
Are all prerequisites installed? Do you get any warnings re-running cmake .. in the build directory?
So far I have no clue 