int prot, int flags, int fd, long offset) {
int prot, int flags, int fd, Offset offset) {
  public static Address mmap(Address address, int size,                                 int prot, int flags, int fd, long offset) {    if (VM.VerifyAssertions)      VM._assert(isPageAligned(address) && isPageMultiple(size) && isPageMultiple(offset));    return VM_SysCall.sysMMapErrno(address,Extent.fromIntSignExtend(size), prot, flags, fd, offset);  }