now errors out if built with off_t > 32 bits but without strtoll()

other curl code

help if libz is available using #ifdef in the source instead, to allow the
distributed source code to be easier built with compressed help text.

it named "--ftp-port" as the additional dash between the words is used in
several other options and this makes it more consistant.

(at least).

in a slightly better way for more platforms. The $HOME is only used for
.curlrc atm, but the possible upcoming change of .netrc treatment may also
need the home dir.

a numeric argument can better bail out if given a weird parameter. This
catches situations such as "-y -Y 2000" or "-O -C [URL]" etc.

by the maketgz script so in releases this is replaced by an actual string.

of explanations.