circleci ccache (#4906)

circle.yml

@@ -9,11 +9,12 @@ checkout:
 
 ## Customize dependencies
 dependencies:
+  cache_directories:
+    - "~/.ccache"
   pre:
     - docker pull px4io/px4-dev-nuttx-gcc4.9
-    - docker info
 
 test:
   override:
-    #- sudo docker run --rm -v `pwd`:`pwd`:rw -v $HOME/.ccache:$HOME/.ccache:rw -e CCACHE_DIR=$HOME/.ccache -w=`pwd` --user=$UID -it px4io/px4-dev-base /bin/bash -c "make"
-    - docker run -v `pwd`:`pwd`:rw -w=`pwd` --user=$UID -it px4io/px4-dev-nuttx-gcc4.9 /bin/bash -c "make px4fmu-v4_default"
+    - docker run --rm -v `pwd`:`pwd`:rw -w=`pwd` -v $HOME/.ccache:$HOME/.ccache:rw -e CCACHE_DIR=$HOME/.ccache --user=$UID -it px4io/px4-dev-nuttx-gcc4.9 /bin/bash -c "ccache -z; make px4fmu-v4_default; ccache -s"
+