Only attempt to link against a framework if building for mac
Only attempt to link against a framework if building for mac

Rust-SDL2/rust-sdl2,Cobrand/rust-sdl2,Cobrand/rust-sdl2,Rust-SDL2/rust-sdl2,AngryLawyer/rust-sdl2,Rust-SDL2/rust-sdl2,Cobrand/rust-sdl2