25 second compile time is not all that bad. This far from the worse example of
compile times in Mesa.

I'm tempted to close this bug as I'm not convinced there is anything special
about Trine 3 here. Are you able to use the perf tool to see where in the
compiler we are spending lots of time? Or at the very least grab an apitrace
[1] of the game at startup and upload it somewhere so that I can use this to
take a quick look.

[1] https://github.com/apitrace/apitrace/wiki/Steam