Add winstone args (#864)

Author: timja

src/main/java/org/jenkinsci/maven/plugins/hpi/RunMojo.java

@@ -108,6 +108,12 @@ public class RunMojo extends AbstractHpiMojo {
             defaultValue = "-Xms512M -Xmx1G -XX:+HeapDumpOnOutOfMemoryError @{jenkins.addOpens}")
     protected String jvmArgs;
 
+    /**
+     * Arguments to pass to Winstone, e.g. --enable-future-java.
+     */
+    @Parameter(property = "maven.hpi.winstoneArgs")
+    protected String winstoneArgs;
+
     @Inject
     private BuildPluginManager pluginManager;
 
@@ -437,6 +443,10 @@ public void execute() throws MojoExecutionException, MojoFailureException {
             cmd.add("--prefix=" + prefix);
         }
 
+        if (winstoneArgs != null) {
+            cmd.add(winstoneArgs);
+        }
+
         getLog().info("Launching Jenkins: " + String.join(" ", cmd));
 
         ProcessBuilder pb = new ProcessBuilder(cmd);