ARM64: Add build infrastructure and initial port of interpreter.

src/lj_frame.h

@@ -159,6 +159,15 @@ enum { LJ_CONT_TAILCALL, LJ_CONT_FFI_CALLBACK };  /* Special continuations. */
 #define CFRAME_SIZE		64
 #endif
 #define CFRAME_SHIFT_MULTRES	3
+#elif LJ_TARGET_ARM64
+#define CFRAME_OFS_ERRF		196
+#define CFRAME_OFS_NRES		200
+#define CFRAME_OFS_PREV		160
+#define CFRAME_OFS_L		176
+#define CFRAME_OFS_PC		168
+#define CFRAME_OFS_MULTRES	192
+#define CFRAME_SIZE		208
+#define CFRAME_SHIFT_MULTRES	3
 #elif LJ_TARGET_PPC
 #if LJ_TARGET_XBOX360
 #define CFRAME_OFS_ERRF		424