Add cache to cmake third_party in TravisCI.

.travis.yml

 language: cpp
-cache: ccache
+cache:
+  directories:
+    - $HOME/third_party
+    - $HOME/.ccache
+
 sudo: required
 dist: trusty
 os:
@@ -35,6 +39,7 @@ addons:
       - clang-format-3.8
       - automake
       - libtool
+      - ccache
 before_install:
   - |
     if [ ${JOB} == "BUILD_AND_TEST" ]; then

paddle/scripts/travis/build_and_test.sh

@@ -6,14 +6,14 @@ if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
   export PYTHONPATH=/opt/python/2.7.12/lib/python2.7/site-packages
   export PYTHONHOME=/opt/python/2.7.12
   export PATH=/opt/python/2.7.12/bin:${PATH}
-  cmake .. -DON_TRAVIS=ON -DON_COVERALLS=ON -DCOVERALLS_UPLOAD=ON
+  cmake .. -DON_TRAVIS=ON -DON_COVERALLS=ON -DCOVERALLS_UPLOAD=ON ${EXTRA_CMAKE_OPTS}
   NRPOC=`nproc`
   make -j $NPROC
   make coveralls
   sudo make install
 elif [[ "$TRAVIS_OS_NAME" == "osx" ]]; then
   export PYTHONPATH=/usr/local/lib/python2.7/site-packages
-  cmake .. -DON_TRAVIS=ON -DON_COVERALLS=ON -DCOVERALLS_UPLOAD=ON
+  cmake .. -DON_TRAVIS=ON -DON_COVERALLS=ON -DCOVERALLS_UPLOAD=ON ${EXTRA_CMAKE_OPTS}
   NPROC=`sysctl -n hw.ncpu`
   make -j $NPROC
 fi

paddle/scripts/travis/common.sh

@@ -2,3 +2,5 @@
 set -e
 mkdir -p ../../../build
 cd ../../../build
+mkdir -p $HOME/third_party
+EXTRA_CMAKE_OPTS="-DTHIRD_PARTY_PATH=${HOME}/third_party"

paddle/scripts/travis/docs.sh

@@ -4,7 +4,7 @@
 source ./common.sh
 
 # Compile Documentation only.
-cmake .. -DCMAKE_BUILD_TYPE=Debug -DWITH_GPU=OFF -DWITH_DOC=ON
+cmake .. -DCMAKE_BUILD_TYPE=Debug -DWITH_GPU=OFF -DWITH_DOC=ON ${EXTRA_CMAKE_OPTS}
 make paddle_docs paddle_docs_cn
 
 # check websites for broken links