Steps:
1) added `brew install libffi`, was told it was already installed and to try reinstalling.
2) changed to `brew reinstall libffi`, was told it was "keg only" and was provided the PKG_CONFIG export statement.
3) added export statement, seems to work.
This makes it simpler in the future to have branches that have dependencies that are different from master, rather than having a single image with all necessary dependencies installed, which may at some point end up not being possible to do.
Currently will remain disabled everywhere, but this allows for enabling LTO for optimized, non-xcode jobs just by changing the value of the LTO variable.
Moving it out of the same directory as the git repository means that the object files won't be copied into the temporary docker container when it's being created.
Currently the MP unit tests will randomly fail due to one of the two background wesnoth instances failing video initialization. All unit tests require the display server to be initialized however, or they fail with the same error as the MP tests sometimes fail with. However, the MP tests are the only tests to randomly fail due to video initialization, while for the same travis job the WML unit tests (which run before) and the boost unit tests (which run after) are still able to be successfully completed.
Therefore, the video initialization failures are not entirely random, and the MP tests are also the only tests that experience this failure while also being the only tests that have more than one instance of wesnoth running simultaneously.
tl;dr: the attempted solution here is to sleep for 5 seconds between starting background processes in the mp unit test script.
Also removes starting the display server prior outside of the docker container, since that's not needed anymore.
Travis runs all commands in .travis.yml in its own wrapper script, so by sourcing steps/script.sh and then using exit explicitly, it resulted in the entire travis wrapper immediately terminating. With steps/script.sh no longer sourced, using exit works as expected again, and only exits steps/script.sh rather than quitting everything. Another solution, should sourcing steps/script.sh become necessary, is to use return instead of exit.
With that addressed, it's then possible to re-add printing the ccache statistics after the build ends while also making sure that the script exits with the return code of the xcodebuild/cmake+make command rather than the return code of the ccache statistics commands.
Travis looks at the return code of the final command run, and since printing the ccache statistics never fails, building would never be considered as failing. Manually calling exit also causes travis to treat the build as errored, since by sourcing the build it results in the entire travis wrapper shell exiting.
This code ended up ignoring *all* MP test failures, in particular the one
fixed in commit 11d7b9f0cf.
I'd test the code and fix it if I could, but unfortunately I can no longer
develop on GNU/Linux because of PC issues (which I mentioned in Discord).
Therefore I'm just reverting the entire change.
This also removes the included SHA1 and MD5 implementations
in favour of those from OpenSSL.
Thanks to @jyrkive for helping to get the CMake build working and
ensuring the game still compiles with OpenSSL 1.1.0.
(The SHA_xxx() aliases were removed in OpenSSL 1.1.0.)
