Bug#993343: OpenLDAP 2.5 FTBFS on GNU/Hurd: MAXPATHLEN undeclared

[Ryan Tandy <ryan@nardis.ca>]

Source: openldap
Version: 2.5.5+dfsg-1~exp1
Severity: important
Tags: upstream ftbfs help
Forwarded: https://bugs.openldap.org/show_bug.cgi?id=9658

https://buildd.debian.org/status/fetch.php?pkg=openldap&arch=hurd-i386&ver=2.5.5%2Bdfsg-1%7Eexp1&stamp=1623486618&raw=0

libtool: compile:  cc -g -O2 -I../../include -I../../include -DLDAP_LIBRARY -c request.c  -fPIC -DPIC -o .libs/request.o
In file included from ldap-int.h:119,
                from request.c:53:
request.c: In function 'ldap_dump_connection':
../../include/ldap_pvt.h:181:25: error: 'MAXPATHLEN' undeclared (first use in this function)
 181 | #define LDAP_IPADDRLEN (MAXPATHLEN + sizeof("PATH="))
     |                         ^~~~~~~~~~
request.c:859:17: note: in expansion of macro 'LDAP_IPADDRLEN'
 859 |    char    from[LDAP_IPADDRLEN];
     |                 ^~~~~~~~~~~~~~
../../include/ldap_pvt.h:181:25: note: each undeclared identifier is reported only once for each function it appears in
 181 | #define LDAP_IPADDRLEN (MAXPATHLEN + sizeof("PATH="))
     |                         ^~~~~~~~~~
request.c:859:17: note: in expansion of macro 'LDAP_IPADDRLEN'
 859 |    char    from[LDAP_IPADDRLEN];
     |                 ^~~~~~~~~~~~~~
Makefile:435: recipe for target 'request.lo' failed
make[2]: *** [request.lo] Error 1

I confirmed locally that current git master is still affected.

It's well-known that GNU/Hurd doesn't provide MAXPATHLEN.
https://www.gnu.org/software/hurd/hurd/porting/guidelines.html#PATH_MAX_tt_MAX_PATH_tt_MAXPATHL

I don't have the bandwidth to work on this myself. It would be great if 
someone from the Hurd community could look at it.

thanks
Ryan