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

Makefile

@@ -6,6 +6,14 @@
 COMPILE_PLATFORM=$(shell uname | sed -e 's/_.*//' | tr '[:upper:]' '[:lower:]' | sed -e 's/\//_/g')
 COMPILE_ARCH=$(shell uname -m | sed -e 's/i.86/x86/' | sed -e 's/^arm.*/arm/')
 
+#arm64 hack!
+ifeq ($(shell uname -m), arm64)
+  COMPILE_ARCH=arm64
+endif
+ifeq ($(shell uname -m), aarch64)
+  COMPILE_ARCH=arm64
+endif
+
 ifeq ($(COMPILE_PLATFORM),sunos)
   # Solaris uname and GNU uname differ
   COMPILE_ARCH=$(shell uname -p | sed -e 's/i.86/x86/')
@@ -471,6 +479,10 @@ ifeq ($(PLATFORM),darwin)
     OPTIMIZEVM += -mfpmath=sse
     BASE_CFLAGS += -arch x86_64
   endif
+  ifeq ($(ARCH),arm64)
+    HAVE_VM_COMPILED=false # TODO: implement compiled vm
+    BASE_CFLAGS += -arch arm64
+  endif
 
   # When compiling on OSX for OSX, we're not cross compiling as far as the
   # Makefile is concerned, as target architecture is specified as a compiler