We'd like to add HP/UX to the list of supported platforms, but have
run into an interesting issue to do with file name lengths.

The pkg_install code uses FILENAME_MAX in a lot of places to represent
the full path name of a file.  Traditionally on BSD systems, this has
been set to 1024 in stdio.h, and derives from the limit on FFS.
MAXPATHLEN is 1024 (via PATH_MAX).

On HP/UX, it seems that FILENAME_MAX is 14, which relates to the V6
filesystem limit.  This may also be the same as other System V derived
Unices, it's been a while since I worked on them.  On HP/UX,
MAXPATHLEN is 1024.

I'd like to replace all the occurrences of FILENAME_MAX in the
pkg_install utilities with MAXPATHLEN.  This is for 2 reasons -
MAXPATHLEN more accurately represents what the buffers will be used to
hold, and I'd like the utilities to work on HP/UX.

If you have a system where MAXPATHLEN is less than FILENAME_MAX, or
where this may cause a problem, could you let me know, please?

Thanks,
Alistair