make it possible to build without an internet connection

java/libraries/javafx/build.xml

@@ -25,6 +25,13 @@
     </and>
   </condition>
 
+  <available file="${gluon.base}.zip" property="javafx.present" />
+
+  <!-- ok to ignore failed downloads if we at least have a version that's local -->
+  <condition property="javafx.ignorable" value="false" else="true">
+    <isset property="javafx.present" />
+  </condition>
+
   <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
 
   <!--
@@ -63,6 +70,7 @@
   <target name="retrieve-gluon">
     <get src="https://download2.gluonhq.com/openjfx/${gluon.version}/openjfx-${gluon.version}_${platform.name}-x64_bin-sdk.zip"
          dest="${gluon.base}.zip"
+         ignoreerrors="${javafx.ignorable}"
          usetimestamp="true" />
 
     <antcall target="unzip-gluon-jars" />