work. This is supposed to detect cross-compiling and alert the user, and not
do the POSIX-check for strerror_r() if it already detected a glibc-compatible
strerror_r().

to/from, based on a suggestion from Alexander Krasnostavsky

the user.
2 - don't check for POSIX-style if glibc-style is found first

don't have one

Pointed out by Chris Gaukroger.

as they are probably very rarely intresting to the "common people" anyway.

doing proxy authentication.

content-type after a transfer.

previous difference was not clear nor documented properly). They can now both
be used interchangeably, but we prefer UPLOAD to PUT since it is a more
generic term.

might be done differently in the future.

function fails and it returns NULL