[ue4] Can't subclass components, linker complains

[badlogic]

http://esotericsoftware.com/forum/UE4-unresolved-external-symbol-spFloatArray-dispose-9106

[badlogic]

This appears to be impossible. UBT won't generate exported symbols for C functions either using the MODULE_API macro, or explicitly using __declspec on MSVC. The resulting .lib file never includes the exported C function symbols.

[badlogic]

Seems to work with explicit __declspec, needed to clean intermediates after code change. Doesn't work using MODULE_API macro.

[badlogic]

Introduced dll.h in spine-c, defines SP_API. Every spine-c function needs to be prefixed with this macro in its header file. For UE4 the SPINEPLUGIN_API is evaluated and eventually replaced with the correct __declspec`. For users wanting to compile Spine into a dll on Windows, users can simply set `SPINEPLUGIN_API` to `DLLEXPORT` for dll compilation and DLLIMPORT` for linking to the dll from user code.

[badlogic]

Closed via 91d44b2