csv was handling non-string keys fine except for the error message
generated when a non-string key was not in 'fieldnames'.

Fix by Tomas Grahn, full patch-with-test by Vajrasky Kok (tweaked slightly).

Also, add a link to the Babel package.

to avoid reporting success on empty tests.

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.