diff --git a/.travis.yml b/.travis.yml
index 0e7d0d6..f96e9a6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,15 @@ language: cpp
 
 compiler: clang
 
+os: linux
+addons:
+  apt:
+    sources:
+      - ubuntu-toolchain-r-test
+    packages:
+      - clang-6.0
+      - clang
+
 before_install:
  - sudo add-apt-repository --yes ppa:ubuntu-sdk-team/ppa
  - sudo apt-get update -qq