Adam Strzelecki to SDL When using deployment in Xcode we use 10.4 SDK for PPC & i386 and 10.6 SDK for x86_64 unfortunately MAC_OS_X_VERSION_10_6 is defined only in 10.6 SDK, in older SDKs it is undefined which makes >= comparison return always TRUTH, so the GCC complains about undefined <NSWindowDelegate>, even if the original intention was to omit <NSWindowDelegate> on older SDKs. Solution, don't relay on MAC_OS_X_VERSION_10_6 but use OSX revision number 1060 directly as SDL does in many other places.