Only set CMAKE_OSX_DEPLOYMENT_TARGET on new macOS

We set `CMAKE_OSX_DEPLOYMENT_TARGET` to make the package compatible with
older macOS than the one we're building on.

However, we should not do this when building on an even older system,
e.g. macOS 10.4

CMakeLists.txt

@@ -395,7 +395,7 @@ if(APPLE)
     set(MACOSX_BUNDLE_REQUIRED_PLATFORM IPhoneOS)
     set_target_properties(${BIN_TARGET} PROPERTIES XCODE_ATTRIBUTE_TARGETED_DEVICE_FAMILY "1,2")
     set(CMAKE_OSX_DEPLOYMENT_TARGET "9.0")
-  else()
+  elseif(DARWIN_MAJOR_VERSION GREATER_EQUAL 16)
     set(MACOSX_BUNDLE_REQUIRED_PLATFORM Carbon)
     set(CMAKE_OSX_DEPLOYMENT_TARGET "10.12.0")
   endif()