fixes symengine#177

Author: ShikharJ

.travis.yml

@@ -5,6 +5,9 @@ compiler:
 os:
   - linux
   - osx
+cache:
+  directories:
+  - $HOME/.ccache
 sudo: false
 addons:
   apt:

bin/install_travis.sh

@@ -3,7 +3,7 @@
 # symengine's bin/install_travis.sh will install miniconda
 conda update -q -n root conda
 
-export conda_pkgs="python=${PYTHON_VERSION} pip cython nose pytest"
+export conda_pkgs="python=${PYTHON_VERSION} pip cython nose pytest ccache"
 
 if [[ "${WITH_SYMPY}" != "no" ]]; then
     export conda_pkgs="${conda_pkgs} sympy";
@@ -21,3 +21,9 @@ fi
 
 conda install -q ${conda_pkgs}
 source activate $our_install_dir;
+
+# Use ccache
+export CXX="ccache ${CXX}"
+export CC="ccache ${CC}"
+export CCACHE_DIR=$HOME/.ccache
+ccache -M 400M