The libXNVCtrl library is used by several programs in nixpkgs to get
Nvidia GPU stats, and they all load the library dynamically, but the
libXNVCtrl package only builds a static library. There is no build flag
to enable this, so we have to patch the Makefile to produce a shared
library.
Based on a patch by @negativo17 for Fedora.
https://github.com/negativo17/nvidia-settings/blob/master/nvidia-settings-libXNVCtrl.patch
