gdm does not build under NetBSD (3.99.16).  The daemon/gdmconfig.c and daemon/server.c files use the setpriority(2) function so, according to the manual page, they have to include sys/resource.h.  They currently do not include it.

The problem is that these files use PRIO_MAX, PRIO_MIN and PRIO_PROCESS definitions, all of which are only defined by the sys/resource.h header file in the NetBSD operating system.  The fix is trivial: include this header file in both files.

I have checked NetBSD, Solaris and Linux, and all three have sys/resource.h, so including it does not seem to be a portability problem.  In case you do not want to include it unconditionally, please DO NOT add a '#if defined(__NetBSD__)' to guard their inclusion.  Just tell me and I'll came up with an appropriate configure patch (if it's really needed).