Update travis build script.

.travis.yml

@@ -28,18 +28,6 @@ matrix:
             - cmake
             - cmake-data
       env: CXX_COMPILER=g++-5 C_COMPILER=gcc-5
-    - compiler: clang
-      addons:
-        apt:
-          sources:
-            - george-edison55-precise-backports
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.6
-          packages:
-            - clang-3.6
-            - cmake
-            - cmake-data
-      env: CXX_COMPILER=clang++-3.6 C_COMPILER=clang-3.6
     - compiler: clang
       addons:
         apt:
@@ -57,6 +45,4 @@ before_install:
   - sudo apt-get update -qq
   - sudo apt-get install -y libopencv-dev
 script:
-  - mkdir build
-  - cd build
-  - cmake -DCMAKE_CXX_COMPILER=$CXX_COMPILER -DCMAKE_C_COMPILER=$C_COMPILER .. && ./dev/run-tests.sh
+  - ./dev/travis-run-tests.sh

dev/travis-run-tests.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+SRC=`pwd`
+
+rm -rf /tmp/build
+mkdir -p /tmp/build
+cd /tmp/build
+if [ ! -d "optional" ]; then
+    mkdir -p optional
+    curl -Ls https://api.github.com/repos/akrzemi1/Optional/tarball | tar --strip-components=1 -xz -C optional
+fi
+cmake -DCMAKE_CXX_COMPILER=$CXX_COMPILER -DCMAKE_C_COMPILER=$C_COMPILER -DEXPERIMENTAL_OPTIONAL_INCLUDE=/tmp/build/optional ${SRC}
+
+make -j8 tests && ./tests/tests