iirc, you also need kernel-headers and maybe one other with a similar name (with my debian based Devuan).
I thought the package build essentials would have dragged it into the install as a dependeant.
With a blank screen and no prompt, I'm not sure what to do.
I would reboot.
Can you boot back into single-user mode, at the grub prompt?
If you can do that, try and reset the xconfig file.
sometimes found /etc/X11/xorg.conf
then copy the new file over the old file and restart the x server (well, reboot to see if the OS gives you a display).