SDL2 libs names

Hi,

I would like to know why, the following libs are named

libSDL2_image.so.1.1
libSDL2_ttf.so.0.1

and not

libSDL2_image-2.0.so.0
libSDL2_ttf-2.0.so.0

Ports:
devel/sdl2-image
devel/sdl2_ttf

Is it because of CMAKE_SHARED_LIBRARY_SUFFIX ? How does it work?

Thank you.