diff --git a/.appveyor.yml b/.appveyor.yml
index 6965cf0da..8431da37d 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -13,5 +13,5 @@ install:
 
 build_script:
   - 'echo building...'
-  - '%CYGWIN%\bin\bash -lc "cd $APPVEYOR_BUILD_FOLDER; exec 0</dev/null; make"'
+  - '%CYGWIN%\bin\bash -lc "cd $APPVEYOR_BUILD_FOLDER; exec 0</dev/null; make +ack"'