By default, ccache tries to give as few false cache hits as
possible. However, in certain situations it’s possible that
you know things that ccache can’t take for granted.
[The CCACHE_SLOPINESS environment variable] makes it possible
to tell ccache to relax some checks in order to increase the
hit rate.
We can relax the ctime/mtime header checks:
- include_file_ctime
By default, ccache also will not cache a file if it
includes a header whose ctime is too new. This option
disables that check.
- include_file_mtime
By default, ccache will not cache a file if it includes
a header whose mtime is too new. This option disables
that check.
We also add a call to clear the cache statistics before running
the build, and display them when the build finishes.
See https://docs.travis-ci.com/user/caching/#ccache-cache
Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>