Revert "renpy: drop RENPY_DEPS_INSTALL"

This reverts commit d151e48c63.

The commit dropping `RENPY_DEPS_INSTALL` support [1] is present only on
the master branch which is not yet released.

[1]:https://github.com/renpy/renpy/commit/f2d3e0d20e2e4267bf9ff0bd0d482f1fd4a5a2fc

pkgs/by-name/re/renpy/package.nix

@@ -65,6 +65,20 @@ stdenv.mkDerivation (finalAttrs: {
       tkinter
     ]);
 
+  RENPY_DEPS_INSTALL = lib.concatStringsSep "::" [
+    ffmpeg.lib
+    freetype
+    fribidi
+    glew.dev
+    harfbuzz.dev
+    libGL
+    libGLU
+    libpng
+    SDL2
+    (lib.getDev SDL2)
+    zlib
+  ];
+
   enableParallelBuilding = true;
 
   patches = [