fix collison of draw-bitmap with GC bitmap under Windows; merge to 5.0.1
fix collison of draw-bitmap with GC bitmap under Windows; merge to 5.0.1

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket