exists in 3.4 but apparently wasn't done for 3.3).

on a system with SO_REUSEPORT defined in the headers but run on a system
with an OS kernel that does not support that reasonably new socket option.

A variable was declared below the top of a block and one function was using
a K&R C style function declaration!

PATH_MAX is not declared on IRIX nor Windows.

the fullpath buffer, not PATH_MAX. fullpath is declared using MAXPATHLEN or
MAX_PATH depending on the OS, and PATH_MAX is not declared on IRIX.

the env_home buffer, not PATH_MAX+1. env_home is declared using MAXPATHLEN+1,
and PATH_MAX is not declared on IRIX.