lprng currently FTBFS on hurd-i386, because MAXPATHLEN is not defined
for GNU/Hurd. POSIX says it is optional when there is no hard limit.
The inlined patch below defines that value to 4096 for GNU. Since lprng
does not seen to be the Debian default, cups is, this small patch can
be used to make lprng available until all cups tests are OK for Hurd.
Looking at the code it seems to be rather easy to write a proper patch
for lprng, not using MAXPATHLEN at all to send upstream. However, I
have chosen not to do this until now. No new release has been made
since February 2011 and it looks like lprng is no longer developed