< The __MAC_10_15 define may not exist on devices running < 10.15, resulting in this section not being appropriately avoided during compilation. Swapping to 101

< The __MAC_10_15 define may not exist on devices running < 10.15, resulting in this section not being appropriately avoided during compilation. Swapping to 101500 should work for all versions of macOS. So they are mindful of people with old Macs. This is good!