Fix error on Travis for JRuby.

tgxworld · tgxworld · commit 7ebbf2c86e08 · 2015-05-27T16:38:39.000+08:00
diff --git a/.travis.yml b/.travis.yml
@@ -9,3 +9,6 @@ rvm:
   - ruby-head
 matrix:
   fast_finish: true
+env:
+  global:
+    - "JRUBY_OPTS=-Xcext.enabled=true"
