POSTINSTALL

  There are two ways to use ccache. You can either prefix your compilation
  commands with ccache or you can let ccache masquerade as the compiler by
  prepending /usr/lib/ccache to your $PATH environment variable. The first
  method is most convenient if you just want to try out ccache or wish to
  use it for some specific projects. The second method is most useful for
  when you wish to use ccache for all your compilations.

  You can also set CC and CXX like so,
  export CC='ccache gcc' ; export CXX='ccache g++' to /etc/pkgmk.conf
  But this method can break on some packages not expecting a space in
  CC or CXX.

  You might also want to change the ccache directory, using the CCACHE_DIR
  environement variable. (I personally use
  export CCACHE_DIR="/var/cache/ccache").

  You may also want to use distcc as a backend to ccache by setting
  export CCACHE_PREFIX="distcc"

  Also if you plan to use this same cache between different crux versions and
  compiler versions, you can do something like this
  export CCACHE_COMPILERCHECK="%compiler% -dumpversion; crux"
  to prevent cache errors.