Reorganized some CPU structures a bit and fixed inappropriate behavior of some mem.c functions on 64-bit binaries (and made mem.c aware of ARM64 as well), fixes both 64-bit recompilers, closes #1215.

src/codegen_new/codegen_backend_arm64.c

@@ -332,13 +332,9 @@ void codegen_backend_init()
 
 	codegen_allocator_clean_blocks(block->head_mem_block);
 
-#if !defined _MSC_VER || defined __clang__
 	asm("mrs %0, fpcr\n"
                 : "=r" (cpu_state.old_fp_control)
 	);
-#else
-	cpu_state.old_fp_control = _controlfp();
-#endif
 }
 
 void codegen_set_rounding_mode(int mode)