set executable flag of gradlew on Linux and Mac

Author: codeanticode

src/processing/mode/android/AndroidBuild.java

@@ -939,7 +939,11 @@ private File createTempBuildFolder(final Sketch sketch) throws IOException {
 
   private void installGradlew(File exportFolder) throws IOException {
     File gradlewFile = mode.getContentFile("mode/gradlew.zip");
-    AndroidUtil.extractFolder(gradlewFile, exportFolder, true, true); 
+    AndroidUtil.extractFolder(gradlewFile, exportFolder, false, true);
+    if (Platform.isMacOS() || Platform.isLinux()) {
+      File execFile = new File(exportFolder, "gradlew");    
+      execFile.setExecutable(true);      
+    }    
   }