addOpenGLRunpath: Add new hook for setting RUNPATH.

This hook allows to add NixOS driver libraries path to given ELF
objects' RUNPATH. We use it instead of settings RUNPATH manually
everywhere. It must be invoked in postFixup so that RUNPATH stripping
does not remove the path.

It puts the path first instead of last so that system-wide drivers
are always preferred.

pkgs/build-support/add-opengl-runpath/default.nix

@@ -0,0 +1,12 @@
+{ lib, stdenv }:
+
+stdenv.mkDerivation {
+  name = "add-opengl-runpath";
+
+  driverLink = "/run/opengl-driver" + lib.optionalString stdenv.isi686 "-32";
+
+  buildCommand = ''
+    mkdir -p $out/nix-support
+    substituteAll ${./setup-hook.sh} $out/nix-support/setup-hook
+  '';
+}