Don't set the "has_openssl" variable if yassl or polarssl is found as
they will simply not work as 100% drop-in replacements for some of the
stuff the "OpenSSL" feature is used for.

I spotted this problem when doing test runs with PolarSSL builds.

Curl_socket returns CURLE_COULDNT_CONNECT when the opensocket callback
returns CURL_SOCKET_BAD. Previous return value CURLE_FAILED_INIT
conveys incorrect information to the user.

Reworked the command sending from two specific LIST and RETR command
functions into a single command based function as well as the two
associated response handlers into a generic command handler.

By modifying the parameter list for ourWriteOut() and passing the
OutStruct that collects data in tool_operate, we get access to the
remote name that we're writing to. Shell scripters should find this
useful when used in conjuntion with the --remote-header-name option.

If an empty string is passed to CURLOPT_SSH_PUBLIC_KEYFILE, libcurl will
pass no public key to libssh2 which then tries to compute it from the
private key. This is known to work when libssh2 1.4.0+ is linked against
OpenSSL.

This change replaces RFC 2818 based hostname check in OpenSSL build with
RFC 6125 [1] based one.

The hostname check in RFC 2818 is ambiguous and each project implements
it in the their own way and they are slightly different. I check curl,
gnutls, Firefox and Chrome and they are all different.

I don't think there is a bug in current implementation of hostname
check. But it is not as strict as the modern browsers do. Currently,
curl allows multiple wildcard character '*' and it matches '.'. (as
described in the comment in ssluse.c).

Firefox implementation is also based on RFC 2818 but it only allows at
most one wildcard character and it must be in the left-most label in the
pattern and the wildcard must not be followed by any character in the
label.[2] Chromium implementation is based on RFC 6125 as my patch does.
Firefox and Chromium both require wildcard in the left-most label in the
presented identifier.

This patch is more strict than the current implementation, so there may
be some cases where old curl works but new one does not. But at the same
time I think it is good practice to follow the modern browsers do and
follow the newer RFC.

[1] http://tools.ietf.org/html/rfc6125#section-6.4.3
[2] https://bugzilla.mozilla.org/show_bug.cgi?id=159483

With FOLLOWLOCATION enabled. When a 3xx page is downloaded and the
download size was known (like with a Content-Length header), but the
subsequent URL (transfered after the 3xx page) was chunked encoded, then
the previous "known download size" would linger and cause the progress
meter to get incorrect information, ie the former value would remain
being sent in. This could easily result in downloads that were WAY
larger than "expected" and would cause >100% outputs with the curl
command line tool.

Test case 599 was created and it was used to repeat the bug and then
verify the fix.

Bug: http://curl.haxx.se/bug/view.cgi?id=3510057
Reported by: Michael Wallner

Replaced the hard coded md5 digest length (16) with a preprocessor
constant

It is now possible to calculate the md5 sum as the stream of buffers
becomes known where as previously it was only possible to calculate the
md5 sum of a pre-prepared buffer.

This reverts commit 9f0e1689.

It turned out that "improvement" instead made the fetching of the
certificates unreliable

Bug: http://curl.haxx.se/mail/lib-2012-03/0238.html
Reported by: Tim Heckman

This feature allows the user to specify and use additional POP3
commands such as UIDL and DELE via libcurl's CURLOPT_CUSTOMREQUEST or
curl's -X command line option.

bug: http://curl.haxx.se/mail/lib-2012-03/0278.html

bug: http://curl.haxx.se/mail/lib-2012-03/0255.html

Take in account that h_errno might be a modifiable lvalue not defined as
a C preprocessor macro

curl segfault in debug callback triggered with CURLINFO_HEADER_OUT and size 0

bug: http://curl.haxx.se/bug/view.cgi?id=3511794

Simplified the code to remove the need for a separate "LIST <msg id>"
command handler and state machine and instead use the LIST command
handler for both operations.

Corrected character and line spacing and re-ordered list and retr
functions based on the order of their state machines.

Moved the server greeting response handling code from the statemach_act
functions to separate response functions. This makes the code simpler
to follow and provides consistency with the other responses that are
handled here.

Body data would be forwarded to the client application in both the RETR
and LIST commands even if CURLOPT_NOBODY was specified.

Original wording could lead users in thinking it tries to
somehow parse the filename for a date expression (like
news_2012_03_05.html). It never mentions that it actually
reads the mtime of the file in filesystem.

This allows building of libcurl on DOS using DJGPP 2.04 and Watt-32
sockets. I know there's already Makefile.djgpp, but I find this more
convenient since I'm used to using the ./configure script from other
platforms