Fixed GCC warnings with SDL2
Fixed GCC warnings with SDL2

git-svn-id: ab66a9de07fa9d47c5829c82992f5279466c775f@5336 63c20433-aa62-49bd-875c-5a186b69a8fb

epam/gpac,Bevara/Access-open,porcelijn/gpac,rbouqueau/gpac,DmitrySigaev/gpac,psteinb/gpac,rbouqueau/gpac_brew_travis,ARSekkat/gpac,canatella/gpac,DmitrySigaev/gpac,porcelijn/gpac,vladimir-kazakov/gpac,drakeguan/gpac,aymanelyaagoubi/gpac,drakeguan/gpac,RodolpheFouquet/gpac,rbouqueau/gpac,RodolpheFouquet/gpac,rbouqueau/gpac_brew_travis,ARSekkat/gpac,DmitrySigaev/gpac,aymanelyaagoubi/gpac,epam/gpac,psteinb/gpac,porcelijn/gpac,RodolpheFouquet/gpac,psteinb/gpac,rbouqueau/gpac,DmitrySigaev/gpac,vladimir-kazakov/gpac,canatella/gpac,canatella/gpac,vladimir-kazakov/gpac,drakeguan/gpac,psteinb/gpac,emmanouil/gpac,epam/gpac,epam/gpac,epam/gpac,ARSekkat/gpac,DmitrySigaev/gpac,canatella/gpac,rbouqueau/gpac,aymanelyaagoubi/gpac,aymanelyaagoubi/gpac,RodolpheFouquet/gpac,rbouqueau/gpac,psteinb/gpac,porcelijn/gpac,psteinb/gpac,Bevara/Access-open,rbouqueau/gpac_brew_travis,porcelijn/gpac,nguyen-viet-thanh-trung/gpac,ARSekkat/gpac,Bevara/Access-open,emmanouil/gpac,nguyen-viet-thanh-trung/gpac,nguyen-viet-thanh-trung/gpac,vladimir-kazakov/gpac,emmanouil/gpac,rbouqueau/gpac,nguyen-viet-thanh-trung/gpac,rbouqueau/gpac_brew_travis,drakeguan/gpac,epam/gpac,rbouqueau/gpac_brew_travis,canatella/gpac,drakeguan/gpac,RodolpheFouquet/gpac,nguyen-viet-thanh-trung/gpac,Bevara/Access-open,Bevara/Access-open,rauf/gpac,porcelijn/gpac,rauf/gpac,vladimir-kazakov/gpac,rauf/gpac,gpac/gpac,gpac/gpac,gpac/gpac,nguyen-viet-thanh-trung/gpac,rauf/gpac,aymanelyaagoubi/gpac,vladimir-kazakov/gpac,DmitrySigaev/gpac,rbouqueau/gpac_brew_travis,gpac/gpac,rbouqueau/gpac,gpac/gpac,canatella/gpac,rauf/gpac,gpac/gpac,drakeguan/gpac,aymanelyaagoubi/gpac,Bevara/Access-open,ARSekkat/gpac,gpac/gpac,emmanouil/gpac,canatella/gpac,rbouqueau/gpac,emmanouil/gpac,gpac/gpac,rauf/gpac,RodolpheFouquet/gpac,emmanouil/gpac,ARSekkat/gpac