Crash on launch on macOS 10.11–10.14

[1ec5]

macOS map SDK v0.15.0 crashes on launch on macOS 10.11–10.14 because it was built on macOS 10.15 and has no explicit minimum deployment target. Examples of this crash include mapbox/mapbox-gl-native-ios#195 and mapbox/mapbox-gl-native-ios#205.

Running cmake -G Xcode . -DCMAKE_SYSTEM_NAME=Darwin results in an Xcode project whose targets have the MACOSX_DEPLOYMENT_TARGET build setting unset. This causes the build products to default to a minimum deployment target that is the newest macOS SDK version supported by the current version of Xcode. As on iOS in #16241, the minimum deployment target should instead be the oldest version supported by the macOS map SDK, which is macOS 10.11.0.

This isn’t a problem on iOS, because something causes this code to set the minimum deployment target:

mapbox-gl-native/platform/ios/ios.cmake

Lines 3 to 5 in 488e550

	if(NOT DEFINED IOS_DEPLOYMENT_TARGET)
	set(IOS_DEPLOYMENT_TARGET "9.0")
	endif()

But similar code in the macOS configuration doesn’t run:

mapbox-gl-native/platform/macos/macos.cmake

Lines 1 to 3 in 8229bd1

	if(NOT DEFINED MACOSX_DEPLOYMENT_TARGET)
	set(MACOSX_DEPLOYMENT_TARGET "10.11")
	endif()

/cc @mapbox/maps-ios @mapbox/gl-native

[1ec5]

I wonder if it’s relevant that MACOSX_DEPLOYMENT_TARGET is also a CMake environment variable, unlike IOS_DEPLOYMENT_TARGET.