Merge pull request #2446 from andyli/travis

TravisCI: tmp fix of broken TRAVIS_BUILD_DIR

.travis.yml

@@ -20,6 +20,7 @@ matrix:
     - env: TARGET=cs
 
 before_install:
+  - export TRAVIS_BUILD_DIR=$(pwd) #tmp fix, see https://github.com/travis-ci/travis-build/pull/182
   - sudo apt-get update
   - sudo apt-get install ocaml zlib1g-dev libgc-dev -y
   - git clone https://github.com/HaxeFoundation/neko.git ~/neko && cd ~/neko && make && sudo make install && cd $TRAVIS_BUILD_DIR