LP64/P64 model API issue #1

["William A. Rowe, Jr." <wr...@rowe-clan.net>]

[LP64 refers to long and ptr having 64 bits, int has 32 bits.]
[P64 refers to only 64 bit pointers, 32 bit long and int.]

Issue  #1; the declaration of apr_mmap_offset takes an off_t as
the offset value.

If the API means to jump forward to an arbitrary position anywhere
in the file, the declaration is correct.  However this case is broken;
right now we simply index from starting offset of the mapped file
as originally mapped.

If the API means to jump forward an arbitrary distance in the currently
mapped file, the declaration should be a size_t as the offset.

I believe this API is so broken, we may want to rip out apr_mmap_offset
altogether.

Bill