pencil2d: added ffmpeg dependency; fixed build

Patched qmake files and source repository to correctly acquire Git information
Added ffmpeg dependency

pkgs/by-name/pe/pencil2d/git-inherit.patch

@@ -0,0 +1,13 @@
+--- a/app/app.pro    
++++ b/app/app.pro
+@@ -208,8 +208,8 @@
+
+ GIT {
+     DEFINES += GIT_EXISTS \
+-    "GIT_CURRENT_SHA1=$$system(git --git-dir=.git --work-tree=. -C $$_PRO_FILE_PWD_/../ rev-parse HEAD)" \
+-    "GIT_TIMESTAMP=$$system(git --git-dir=.git --work-tree=. -C $$_PRO_FILE_PWD_/../ log -n 1 --pretty=format:"%cd" --date=format:"%Y-%m-%d_%H:%M:%S")"
++    "GIT_CURRENT_SHA1=$$cat($$_PRO_FILE_PWD_/../COMMIT)" \
++    "GIT_TIMESTAMP=$$cat($$_PRO_FILE_PWD_/../SOURCE_TIMESTAMP_EPOCH)"
+ }
+
+ macx {

pkgs/by-name/pe/pencil2d/package.nix

@@ -3,30 +3,56 @@
   stdenv,
   fetchFromGitHub,
   qt5,
+  git,
+  ffmpeg_6,
+  nix-update-script,
 }:
 
-stdenv.mkDerivation (FinalAttrs: {
+stdenv.mkDerivation (finalAttrs: {
   pname = "pencil2d";
   version = "0.7.0";
 
   src = fetchFromGitHub {
     owner = "pencil2d";
     repo = "pencil";
-    tag = "v${FinalAttrs.version}";
-    hash = "sha256-OuZpKgX2BgfuQdnjk/RTBww/blO1CIrYWr7KytqcIbQ=";
+    tag = "v${finalAttrs.version}";
+    hash = "sha256-l+iW0k3WdNXDwXtt958JJWSe3zNhQVul4FUcPPMrVxE=";
+    leaveDotGit = true;
+    postFetch = ''
+      # Obtain the last commit ID and its timestamp, then zap .git for reproducibility
+      cd $out
+      git rev-parse HEAD > $out/COMMIT
+      # 0000-00-00T00:00:00Z
+      date -u -d "@$(git log -1 --pretty=%ct)" "+%Y-%m-%d_%H:%M:%S" > $out/SOURCE_TIMESTAMP_EPOCH
+      find "$out" -name .git -print0 | xargs -0 rm -rf
+    '';
   };
 
+  patches = [ ./git-inherit.patch ];
+
   nativeBuildInputs = with qt5; [
     qmake
     wrapQtAppsHook
     qttools
+    git
   ];
 
+  qmakeFlags = [
+    "pencil2d.pro"
+    "CONFIG+=release"
+    "CONFIG+=PENCIL2D_RELEASE"
+    "CONFIG+=GIT"
+    "VERSION=${finalAttrs.version}"
+  ];
+
+  passthru.updateScript = nix-update-script { };
+
   buildInputs = with qt5; [
     qtbase
     qtmultimedia
     qtsvg
     qtwayland
+    ffmpeg_6
   ];
 
   meta = {