update .travis.yml

.travis.yml

@@ -1,19 +1,20 @@
+language: rust
 env:
   global:
     - secure: LhiHXBKaxsubX45eMukb39IDKaM0mdMzE8Ow4DCnq/yFTZn22ju/H3nMawk0X74gCMXsrADErcBke/7+mHV5GgToqtKjr8RaZDwAmZtzDgdrvJlqy+w59WbvJKuPXYGN0dPiVSkt/fFGf7qGFjLj0DiGZHw05XmBSq+90Qn3Iqw=
-
-language: rust
-
+  matrix:
+    - LLVM_VERSION=3.4
+    - LLVM_VERSION=3.5
 before_install:
-  - yes | sudo add-apt-repository "deb http://llvm.org/apt/precise/ llvm-toolchain-precise-3.4 main"
+  - yes | sudo add-apt-repository "deb http://llvm.org/apt/precise/ llvm-toolchain-precise-${LLVM_VERSION} main"
   - yes | sudo add-apt-repository "deb http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu precise main"
   - sudo apt-get update
 install:
-  - sudo apt-get install --force-yes libclang-3.4-dev
+  - sudo apt-get install --force-yes libclang-${LLVM_VERSION}-dev
 script:
-  - LIBCLANG_PATH=/usr/lib/llvm-3.4/lib cargo build --verbose
+  - export LIBCLANG_PATH=/usr/lib/llvm-${LLVM_VERSION}/lib
+  - cargo build -v
   - cargo test -v
   - cargo doc
-
 after_script:
   - mv target/doc . && curl http://www.rust-ci.org/artifacts/put?t=$RUSTCI_TOKEN | sh