droidcam and magit improvements

pkgs/v4l2loopback-dc/default.nix

@@ -0,0 +1,32 @@
+{ stdenv, fetchzip, kernel }:
+
+stdenv.mkDerivation rec {
+  pname = "v4l2loopback-dc";
+  version = "0";
+
+  src = fetchzip {
+    url = "https://github.com/dev47apps/droidcam/archive/refs/tags/v1.7.2.zip";
+    sha256 = "1iskvs5p71gkiinj78kkl9ygl5il9rdbzm0h85hwyzm2xwkcybrp";
+  };
+
+  sourceRoot = "source/v4l2loopback";
+
+  KVER = "${kernel.modDirVersion}";
+  KBUILD_DIR = "${kernel.dev}/lib/modules/${kernel.modDirVersion}/build";
+
+  nativeBuildInputs = kernel.moduleBuildDependencies;
+
+  postPatch = ''
+    sed -i -e 's:/lib/modules/$(KERNELRELEASE)/build:${KBUILD_DIR}:g' Makefile
+  '';
+
+  installPhase = ''
+    mkdir -p $out/lib/modules/${KVER}/kernels/media/video
+    cp v4l2loopback-dc.ko $out/lib/modules/${KVER}/kernels/media/video/
+  '';
+
+  meta = with stdenv.lib; {
+    description = "DroidCam kernel module v4l2loopback-dc";
+    homepage = https://github.com/aramg/droidcam;
+  };
+}