Cmake doesn't find opengl on Ubuntu (tried 18.04, 19.04) even after installing the required system dependencies.
libgl1-mesa-dev works instead of mesa-common-dev, as noted here: https://stackoverflow.com/a/47926071/6597851.
* Remove freeglut as dependency for SFML
SFML doesn't use freeglut as dependency.
I'm not familiar enough with vcpkg, but does 'stb' need to be specified as dependency as well? We already include that header, or does vcpkg make sure it replaces it with the latest stb version?
* [sfml] Bump version and remove qualifier from stb dependency
Just replacing export symbols doesn't really do the trick as the config file still won't find the static libraries, by "forcing" the `SFML_STATIC_LIBRARIES` to true when using the static target, the SFMLConfig.cmake and SFMLConfigDependencies.cmake files will properly detect the static libraries and it will also set the config header correctly.
