Property definitions

core $ NativeFile :: file_stat
	fun file_stat: NativeFileStat `{
		struct stat buff;
		if(fstat(fileno(self), &buff) != -1) {
			struct stat* stat_element;
			stat_element = malloc(sizeof(struct stat));
			return memcpy(stat_element, &buff, sizeof(struct stat));
		}
		return 0;
	`}
lib/core/file.nit:1536,2--1544,3