Void maintains
a git repo with build scripts for every package, kind of like the FreeBSD ports tree. You can disable features you aren't using (like in Gentoo, but less powerful) and build your own packages to install with the package manager. If you do want to get into compiling packages yourself, this makes it easier than downloading and compiling everything manually. But keep in mind that if Void doesn't package it, then it isn't in the ports tree either. In that case you have to download and build it manually.