Upgrades to Xcode project and Apple Silicon support

- Reorganized Xcode project
- Added missionpack support to Xcode project
- Incorporated changes from MaddTheSane for Apple Silicon support https://github.com/maddthesane/ioq3
- Built SDL 2.0.14 for Apple Siicon, added to existing SDL dylib
- Built SDLMain for Apple Silicon, added to existing libSDL2main.a

code/qcommon/vm_x86.c

@@ -42,6 +42,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   #endif
 #endif
 
+#if defined (__i386__) || defined(__x86_64__)
 static void VM_Destroy_Compiled(vm_t* self);
 
 /*
@@ -1807,3 +1808,4 @@ int VM_CallCompiled(vm_t *vm, int *args)
 
 	return opStack[opStackOfs];
 }
+#endif