Why single-threaded build by default

[gethiox]

Windows installation guide says:

It will probably take at least 1 hour to download and build.

can't be --parallel <n> or -j<n> added to cmake --build ... command? It saved me an absurd amount of time of time when I re-ran my build with this change after some error fixing, build was complete like under 10 minutes.

Is single thread build really required? I'm not very familiar with cmake but I'm pretty sure it has some --parallel option with cpu core auto detection to avoid placing arbitrary number in a universal build script.