The current versions only have partial C++11 support which fortunately
has caused us only few issues so far but it would be good to finally
have fully working C++11 support. This also gets rid of several CI
builds on very outdated platforms.
The outdated platforms were used to also test CMake 2.8 but as future
versions of CMake will drop combability with CMake < 3.5 this is a good
time to also drop that requirement on our part.
This PR does not remove or update any outdated code.
`MATCHES` does regular expression matching which is not the intended behavior here. `Clang` still requires it since it also needs to match `AppleClang.
Oliver Stöneberg