Try to make travis builds work
diff --git a/.travis.yml b/.travis.yml
index 9253224..16c6297 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,7 +21,7 @@
   - 20.3
   - 19.3
   - 18.2
-  - 18.1
-  - 18.0
   - 17.5
-  - R16B03-1
+
+script:
+  - make check