grafx2: cleaned up libSDL* dependencies (#4556)
grafx2: cleaned up libSDL* dependencies (#4556)

* grafx2: cleaned up libSDL* dependencies

Begasus/haikuports,haikuports/haikuports,nielx/haikuports,Begasus/haikuports,haikuports/haikuports,Begasus/haikuports,moochris/haikuports,moochris/haikuports,haikuports/haikuports,Begasus/haikuports,nielx/haikuports,haikuports/haikuports,nielx/haikuports,Begasus/haikuports,moochris/haikuports,haikuports/haikuports