tuxmath: cleaned libSDL* dependencies (#4555)
tuxmath: cleaned libSDL* dependencies (#4555)

* tuxmath: cleaned libSDL* dependencies
Begasus/haikuports,moochris/haikuports,haikuports/haikuports,haikuports/haikuports,haikuports/haikuports,nielx/haikuports,Begasus/haikuports,Begasus/haikuports,moochris/haikuports,Begasus/haikuports,nielx/haikuports,moochris/haikuports,haikuports/haikuports,haikuports/haikuports,Begasus/haikuports,nielx/haikuports