use the voc's fork of obs

notes:
 - doesn't use niv to manage its sources, since apparently niv doesn't
   support git submodules
 - haven't tested that this actually builds (it does build without the
   blackmagic stuff, which I don't have locally and didn't have the
   patience to fetch)

pkgs/default.nix

@@ -26,7 +26,28 @@ let
 
     blackmagicDesktopVideo = callPackage ./blackmagic-desktop-video { };
 
-    obs-studio = unstable.obs-studio.overrideAttrs (_: rec {
+    obs-studio = unstable.obs-studio.overrideAttrs (old: rec {
+      src = pkgs.fetchgit {
+        url = "https://github.com/lukas2511/obs-studio";
+        rev = "93ae2b1c11ad81787d69f30c6c251f02dc72c2f4";
+        sha256 = "0zla25bjlqx78rb3fgc2yj8bgb4w4lfq6ans47mpb9nvm5ngx5rn";
+        fetchSubmodules = true;
+      };
+
+      buildInputs = old.buildInputs ++ [ pkgs.libdrm ];
+
+      # disable browser-source patches which don't fit on this version of obs
+      patches = [];
+      cmakeFlags = [
+        "-DCMAKE_CXX_FLAGS=-DDL_OPENGL=\\\"$(out)/lib/libobs-opengl.so\\\""
+        "-DOBS_VERSION_OVERRIDE=27.0.1"
+        "-Wno-dev" # kill dev warnings that are useless for packaging
+        # is there a better way to change just one flag? (this is where I miss guix tbh)
+        # anyways turns browser sources off
+        "-DBUILD_BROWSER=OFF"
+        "-DCEF_ROOT_DIR=../../cef"
+      ];
+
       wrapLibraries = with (pkgs // newpkgs); [
         xorg.libX11.out
         libvlc