It looks like builders might be running into some problems I encountered and chalked up to my ancient Fedora 23 and its GCC 5.3.1. To wit:
@jonetsu - You're right, you may have to build libspeex by hand in its directory, but no, don't run make install. You may also need to create a directory at dep/lib/linux_gcc/x64/. If you follow the build sequence in my message to Gmaq you should be all set then for the steps in dep:
That should install glew.a, jansson.a, and libspeexdsp.a in dep/lib/linux_gcc/x64/.
@Gmaq - You might also encounter problems with certain plugin builds. If so, let me know which ones, I'll check 'em out and see if there are anomalies in the build process for them. Also, be aware that any 32-bit build is completely unsupported by the dev, he's signed off on that issue.
I actually didn't think anyone else would bother trying to build it. It's not difficult, you just have to watch out for a few gotchas. I found that at least one plugin codebase refused to build until I rewrote the offending code to accommodate my aging compiler, but you should be safe if you're using a more up-to-date distro. The reference distribution for VCV Rack is Ubuntu 18.04, IIRC.
Sorry for the confusion, let me know how things work out.