diff --git a/.travis.yml b/.travis.yml
index d98abdc7..40990dc7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,9 +9,12 @@ rust:
 
 addons:
   apt:
+    sources:
+      - llvm-toolchain-precise-3.9
     packages:
       - libcfitsio3-dev
       - pkg-config
+      - clang-3.9
 
 matrix:
   allow_failures: