Make sure java knows about javafx's dependencies

shells/javafx.nix

@@ -2,9 +2,19 @@ let
   pkgs = import <nixpkgs> {};
   baseVimConfig = import ../programs/neovim/base.nix { inherit pkgs; };
   jdtls = import ../packages/jdtls/default.nix { inherit pkgs; stdenv = pkgs.stdenv; };
+
+  extraRpath = pkgs.stdenv.lib.strings.makeLibraryPath (with pkgs; [ ffmpeg ]);
 in
 pkgs.mkShell {
   buildInputs = with pkgs; [
+    (
+      pkgs.writeScriptBin "java" ''
+        #!${pkgs.zsh}/bin/zsh
+
+        old_path="$(patchelf --print-rpath ${jdk11}/bin/java)"
+        LD_LIBRARY_PATH="$old_path:${extraRpath}" ${jdk11}/bin/java $@
+      ''
+    )
     jdk11
     jdtls
     openjfx11