signed and unsigned type in conditional expression

Separated the parsing of login details from the processing of them in
parse_url_login() ready for use by setstropt_userpwd().

Re-factored these functions to reflect their new behaviour following the
addition of login options.

Apparently the previous usage didn't work with that implementation,
while this updated version works with at least both Parallel BZIP2
v1.1.8 and regular bzip "Version 1.0.6, 6-Sept-2010".

Standardised the naming of all perform based functions to be in the form
smtp_perform_something().

Curl-config outputs static libraries even when they are disabled in
configure.

This causes problems with the build of pycurl.

Commit c3ea3eb6 introduced some minor cosmetic errors in
curl_mutli_socket_action(3).

These are needed in cases where clock_gettime is used, from librt.

Also note the prohibition on sharing handles across threads.

Updated the coding style, in this function, to be consistant with other
response functions rather then performing a hard return on failure.

Updated the coding style, in this function, to be consistent with other
response functions rather then performing a hard return on failure.

Standardised the naming of all perform based functions to be in the form
pop3_perform_something() following the changes made to IMAP.

Started to apply the same tidy up to the POP3 code as applied to the
IMAP code in the 7.30.0 release.

Added support for specifying the preferred authentication mechanism in
the URL as per Internet-Draft 'draft-earhart-url-smtp-00'.

... to use left-shifted values, like those defined in curl.h, rather
than 16-bit hexadecimal values.

Added support for specifying the preferred authentication type and SASL
mechanism in the URL as per RFC-2384.

Added support for specifying the preferred authentication mechanism in
the URL as per RFC-5092.

... to use left-shifted values, like those defined in curl.h, rather
than 16-bit hexadecimal values.

In preparation for the upcoming changes to IMAP, POP3 and SMTP added
preferred mechanism values.

As well as parsing the username and password from the URL, added support
for parsing the optional options part from the login details, to allow
the following supported URL format:

schema://username:password;options@example.com/path?q=foobar

This will only be used by IMAP, POP3 and SMTP at present but any
protocol that may be given login options in the URL will be able to
add support for them.

warning: unused variable 'smtp' introduced in commit 73cbd21b.

...instead of the 220 we otherwise expect.

Made the ftpserver.pl support sending a custom "welcome" and then
created test 1219 to verify this fix with such a 230 welcome.

Bug: http://curl.haxx.se/mail/lib-2013-02/0102.html
Reported by: Anders Havn

For libc variants without a spearate pthread lib (like bionic), try
using pthreads without the pthreads lib first and only if that fails try
the -lpthread linker flag.

Bug: http://curl.haxx.se/bug/view.cgi?id=1216
Reported by: Duncan

Accessing a file with an absolute path in the root dir but with no
directory specified was not handled correctly. This fix comes with four
new test cases that verify it.

Bug: http://curl.haxx.se/mail/lib-2013-04/0142.html
Reported by: Sam Deane