VirtualBox Hypervisor

What host platform are you working on? That is, is your host computer running some distro of Linux? Or OSX on a Mac? Or Windows?

I used to compile VirtualBox years ago on my #-Link-Snipped-# host, though I haven't done it in years because it's already compiled for me now.

If you are running Linux (or OSX, I think), the GCC compiler and GNU tools are already installed. So if you've already downloaded the source code, you can probably compile it with the standard three commands (installation must be done as root):

configure
make
make install

If you only have a Windows host, you'll have to get compiler and tools first. #-Link-Snipped-# is probably the best choice for this. (Ordinarily I recommend <a href="https://cygwin.com/" target="_blank" rel="nofollow noopener noreferrer">Cygwin</a> for anyone who uses Windows, but if you just want to compile one stand-alone application like VirtualBox, MinGW would probably be easier.)