Linux build occassionally fails in CI

[z64555]

We've been seeing this more recently. Essentially, one or multiple builds on the Linux target fails.

My investigation led me to a failure by cp, a copy command for bash, stating that it could not copy a .so file because it already exists in the destination, which appears to be nonsense.

The line that this call to cp happens in is rather long, making commandline length limit highly probable. The linux length limit of 4096 characters coincidentally has it run this as its last command on the line: cp -a /__w/fs2open.github.com/fs2open.github.com/build/lib

Further investigation revealed that cp is being called by ninja, and the build.ninja file its running on is from cmake, but that's about as far as I got. I suspect there's a configuration not quite right in cmake that's leading to the symptom.

[z64555]

IIRC I had stumbled across this issue very recently when messing around with the pi-pico. The solution with it was to update cmake, so this is a possible solution for this situation as well.

[z64555]

The CMake versions in the linux runners should be the latest release, so that makes it unlikely that upgrading the cmake version will resolve this.

[z64555]

It's possible that there's a configuration with cmake that can limit the commandline options that it generates, but since I'm not familiar with cmake nor how to navigate its documentation I cannot make a reasonable time limit.

Since this issue is mostly an nuisance rather than a progress stopper, I'm demoting the priority and removing it from the 22.2 milestone.