OpenGL includes are ~35k lines together and it is a waste of
compilation time to include them even if they are not needed at all
(e.g. whole SceneGraph and Physics libraries). Saves ~10s of compilation
time (6:46 before, now 6:35).
Optimalizations in Corrade::TestSuite and Corrade::Utility::Debug leaded
to significant reduction of compilation time - on my machine it was
~5:38 before with building of unit tests enabled, now only ~5:00.
Because with NaCl WindowContext doesn't make sense anymore, the classes
are now renamed:
* Contexts namespace -> Platform
* *WindowContext -> Application
Hopefully this is (one of) last crazy renaming runs.
Magnum.h now doesn't include anything except OpenGL headers, thus
changes in Math library don't trigger recompilation of everything, but
only of things really depending on it.
Math constants moved to separate file for similar reasons, de-inlined
some functions to remove the need for some #includes.
* CMAKE_SHARED_LIBRARY_CXX_FLAGS is empty here, caused CMake errors.
* CMake's OBJECT target has a bug that it doesn't define target_EXPORTS
as with other library targets, so it's needed to define it manually.
It also fixes empty flags issue.
* Visibility headers weren't updated for OBJECT targets, they now also
catch *Objects_EXPORTS defines.
Reusing macros MAGNUM_EXPORT and friends already used for Windows
builds. For exported classes added MAGNUM_LOCAL to private members which
are not referenced from any inline function. Added explicit
MAGNUM_EXPORT to private members which are referenced. CMake provides
its own macro <target>_EXPORTS, using that instead of
set_target_properties().