SDL_ttf library for SDL 1.1.5

Alexander Pipelka reminded me that SDL_ttf needed to be changed for the
new alpha blending code in SDL 1.1.5:

This is also a good example of conditional code based on SDL version.

I’ll be releasing these versions of SDL_ttf and SDL_image simultaneously
with the SDL 1.1.5 release.

See ya!
-Sam Lantinga, Lead Programmer, Loki Entertainment Software