#include <xpc/availability.h> also included by <xpc/xpc.h>

xpc/availability.h

Certain parts of the project use all the project's headers but have to build
includes: Availability.h, sys/cdefs.h
1 macro

macroIPHONE_SIMULATOR_HOST_MIN_VERSION_REQUIRED

#define IPHONE_SIMULATOR_HOST_MIN_VERSION_REQUIRED 999999