LFS meets PowerPC - score 0,1

[Paul Eggert]

   Date: Fri, 18 Jun 1999 14:25:44 +1000
   From: Geoff Keating <geoffk@ozemail.com.au>

   Apart from that, it looks OK to me.

I noticed that the code `if(__offset >= (1ULL << 32))' is bogus, since
it is incorrect for some large negative offsets.  E.g. if __offset is
-4294967296, then the code doesn't report a mmap failure, but instead
silently treats __offset as if it were zero.

Also, surely the code meant to set errno to EINVAL, not -EINVAL.

That is, the check should look something like this instead (rewriting
__offset to offset as you suggested):

	if (offset != (off_t) offset)
	  {
	    errno = EINVAL;
	    return MAP_FAILED;
	  }

This is more portable too, since this doesn't assume that off_t is 32 bits.