Fix warning: unexpected cfg condition name: ios_framework

Author: tesuji

sdl2-sys/Cargo.toml

@@ -57,3 +57,7 @@ mixer = []
 image = []
 ttf = []
 gfx = []
+
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = ['cfg(mac_framework)', 'cfg(ios_framework)']