Follow-up fix from 7d80ed64.

The SessionHandle may not be around to use when we restore the sigpipe
sighandler so we store the no_signal boolean in the local struct to know
if/how to restore.

Thoughts around buffer sizes and what might be possible to do...

When the c-ares based resolver backend failed to resolve a name, it
tried to show the name that failed from existing structs. This caused
the wrong output and shown hostname when for example --interface
[hostname] was used and that name resolving failed.

Now we use the hostname used in the actual resolve attempt in the error
message as well.

Bug: http://curl.haxx.se/bug/view.cgi?id=1191
Reported-by: Kim Vandry

When we recently started to treat a zero return code from SSL_read() as
an error we also got false positives - which primarily looks to be
because the OpenSSL documentation is wrong and a zero return code is not
at all an error case in many situations.

Now ossl_recv() will check with ERR_get_error() to see if there is a
stored error and only then consider it to be a true error if SSL_read()
returned zero.

Bug: http://curl.haxx.se/bug/view.cgi?id=1249
Reported-by: Nach M. S.
Patch-by: Nach M. S.

Something (a recent security update maybe?) changed in Lion, and now it
has changed SSLCopyPeerTrust such that it may return noErr but also give
us a null trust, which caught us off guard and caused an eventual crash.

... and restore the ordinary handling again when it returns. This is
done for curl_easy_perform() and curl_easy_cleanup() only for now - and
only when built to use OpenSSL as backend as this is the known culprit
for the spurious SIGPIPEs people have received.

Bug: http://curl.haxx.se/bug/view.cgi?id=1180
Reported by: Lluís Batlle i Rossell

This erroneously run unit test 1310 instead of 1396!

... to prevent failure when a non-default -b option is given

This doesn't need to be in the release notes. I cleaned up a lot of the #if
lines in the code to use MAC_OS_X_VERSION_MIN_REQUIRED and
MAC_OS_X_VERSION_MAX_ALLOWED instead of checking for whether things like
__MAC_10_6 or whatever were defined, because for some SDKs Apple has released
they were defined out of place.

RFC3986 details how a path part passed in as part of a URI should be
"cleaned" from dot sequences before getting used. The described
algorithm is now implemented in lib/dotdot.c with the accompanied test
case in test 1395.

Bug: http://curl.haxx.se/bug/view.cgi?id=1200
Reported-by: Alex Vinnik

Security problem: CVE-2013-2174

If a program would give a string like "%FF" to curl_easy_unescape() but
ask for it to decode only the first byte, it would still parse and
decode the full hex sequence. The function then not only read beyond the
allowed buffer but it would also deduct the *unsigned* counter variable
for how many more bytes there's left to read in the buffer by two,
making the counter wrap. Continuing this, the function would go on
reading beyond the buffer and soon writing beyond the allocated target
buffer...

Bug: http://curl.haxx.se/docs/adv_20130622.html
Reported-by: Timo Sirainen

As a remedy to the problem when a socket gets closed and a new one is
opened with the same file descriptor number and as a result
multi.c:singlesocket() doesn't detect the difference, the new function
Curl_multi_closed() gets told when a socket is closed so that it can be
removed from the socket hash. When the old one has been removed, a new
socket should be detected fine by the singlesocket() on next invoke.

Bug: http://curl.haxx.se/bug/view.cgi?id=1248
Reported-by: Erik Johansson

When performing COOKIELIST operations the cookie lock needs to be taken
for the cases where the cookies are shared among multiple handles!

Verified by Benjamin Gilbert's updated test 506

Bug: http://curl.haxx.se/bug/view.cgi?id=1215
Reported-by: Benjamin Gilbert

It doesn't right now: http://curl.haxx.se/bug/view.cgi?id=1215

Make it clearer that the CURLOPT_PROGRESSFUNCTION callback will be
called more frequently than once per second when things are happening.

Mention 7 recent bug fixes and their associated contributors

When curl_multi_wait() finds no file descriptor to wait for, it returns
instantly and this must be handled gracefully within curl_easy_perform()
or cause a busy-loop. Starting now, repeated fast returns without any
file descriptors is detected and a gradually increasing sleep will be
used (up to a max of 1000 milliseconds) before continuing the loop.

Bug: http://curl.haxx.se/bug/view.cgi?id=1238
Reported-by: Miguel Angel

The initial fix to only compare full path names were done in commit
04f52e9b but found out to be incomplete. This takes should make the
change more complete and there's now two additional tests to verify
(test 31 and 62).

Makes it build on windows

By always returning the md5 for an empty body when auth-int is asked
for, libcurl now at least sometimes does the right thing.

Bug: http://curl.haxx.se/bug/view.cgi?id=1235
Patched-by: Nach M. S.

Allow less room for "triggered too early" mistakes by applications /
timers on non-windows platforms. Starting now, we assume that a timeout
call is never made earlier than 3 milliseconds before the actual
timeout. This greatly improves timeout accuracy on Linux.

Bug: http://curl.haxx.se/bug/view.cgi?id=1228
Reported-by: Hang Su

In the pkcs12 code, we get a list of x509 records returned from
PKCS12_parse but when iterating over the list and passing each to
SSL_CTX_add_extra_chain_cert() we didn't also properly remove them from
the "stack", which made them get freed twice (both in sk_X509_pop_free()
and then later in SSL_CTX_free).

This isn't really documented anywhere...

Bug: http://curl.haxx.se/bug/view.cgi?id=1236
Reported-by: Nikaiw