adding clang 4.0 to builds - probably wont work since the ppa is not yet whitelisted in travis...
diff --git a/.travis.yml b/.travis.yml
index 8493f28..9617d2c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -50,6 +50,7 @@
       - llvm-toolchain-precise-3.7
       - llvm-toolchain-precise-3.8
       - llvm-toolchain-precise-3.9
+      - llvm-toolchain-precise-4.0
 
 compiler: clang
 os: linux
@@ -172,6 +173,13 @@
           packages: ["clang-3.9", "valgrind", "g++-multilib", "libc6-dbg", "libc6-dbg:i386", "g++-6"]
           sources: *apt_sources
 
+    # Clang 4.0
+    - env: COMPILER=clang++-4.0 HAS_ASAN_64=true HAS_UBSAN_64=true
+      addons: &clang40
+        apt:
+          packages: ["clang-4.0", "valgrind", "g++-multilib", "libc6-dbg", "libc6-dbg:i386", "g++-6"]
+          sources: *apt_sources
+
     # Xcode 6.4 Clang
     - env: COMPILER=clang++
       osx_image: xcode6.4