Add missing newhandle free call in push_promise().

Closes #1416

Add missing our_ssl_sessionid free call in mbed_connect_step3().

Closes #1417

This adds -Werror-implicit-function-declaration for GCC 2.95+ so that
these errors are visible at the point where they occur instead of only
at link time.
Implicit function declarations are illegal in C99 and C++ anyway, and
the same warning has been turned into an error for ICC in commit
3072c5b8.

Ref: https://gcc.gnu.org/onlinedocs/gcc-2.95.2/gcc_2.html#SEC8
Ref: https://curl.haxx.se/mail/lib-2017-04/0001.html
Closes https://github.com/curl/curl/pull/1419

Ref: https://github.com/curl/curl/issues/1408
Closes https://github.com/curl/curl/pull/1412

Follow-up to aa573c3c

Ref: https://github.com/curl/curl/pull/1406

If the existing timer is still in there but has expired, the new timer
should be added.

Reported-by: Rainer Canavan
Bug: https://curl.haxx.se/mail/lib-2017-04/0030.html
Closes #1407

Reported-by: Marcel Raad
Fixes #1408
Closes #1409

ssl_session_init was only introduced in version 1.3.8, the penultimate
version. The function only contains a memset, so replace it with that.

Suggested-by: Jay Satiro
Fixes https://github.com/curl/curl/issues/1401

The POSIX standard location is <poll.h>. Using <sys/poll.h> results in
warning spam when using the musl standard library.

Closes https://github.com/curl/curl/pull/1406

Closes #1402

... because they may include an intermediate certificate for a client
certificate and the intermediate certificate needs to be presented to
the server, no matter if we verify the peer or not.

Reported-by: thraidh
Closes #851

Reported-by: Alex Bligh
Bug: https://curl.haxx.se/mail/lib-2017-04/0044.html

Issues and PRs with no activity for 180 days will get marked as stale,
and if no further activity happens within 14 more days, the issue gets
closed.

This follows our established policy of not letting stalled bugs "get in
the way": https://curl.haxx.se/docs/bugs.html#Closing_off_stalled_bugs

Closes #1398

- Change documented param type to char ** from incorrect long *.

--without-ssl is needed instead of --with-winssl.

... by moving the variables into the correct #ifdef block.

Closes #1397

When UNICODE is not defined, the Curl_convert_UTF8_to_tchar macro maps
directly to its argument. As it is declared as a pointer to const and
InitializeSecurityContext expects a pointer to non-const, both MSVC and MinGW
issue a warning about implicitly casting away the const. Fix this by declaring
the variables as pointers to non-const.

Closes https://github.com/curl/curl/pull/1394

Reported-by: Carsten (talksinmath)

Fixes #1384
Closes #1395

Curl_timeleft returns time_t instead of long since commit
21aa32d3.

Previously, periods of fast speed between periods of slow speed would
not count and could still erroneously trigger a timeout.

Reported-by: Paul Harris
Fixes #1345
Closes #1390

Triggered a test failure on test 1541 for the build known as
"Linux 4.4 i686 tcc 0.9.26 glibc 2.20"

Curl_llist_alloc is now Curl_llist_init.

Closes https://github.com/curl/curl/pull/1391

and mention specific issues where they are discussed

... the sizes and the formatting strings are what's really important and
avoids problems with int64_t vs "long long".

Bug: https://curl.haxx.se/mail/lib-2017-04/0019.html

This reverts commit 81284374.

Due to mingw32 brekage.

MinGW complains:
tool_operate.c:197:15: error: comparison is always true due to limited range
of data type [-Werror=type-limits]

Fix this by only doing the comparison if 'long' is large enough to hold the
constant it is compared with.

Closes https://github.com/curl/curl/pull/1378

Ref: https://github.com/curl/curl/pull/1378

Since it is a native type and it makes it less complicated to find a
matching one in system.h

Bug: https://curl.haxx.se/mail/lib-2017-04/0010.html
Reported-by: Dan Fandrich

Closes #1388

This checks the new behavior of Curl_splaygetbest, so that the smallest
node not larger than the key is removed, and FIFO behavior is kept even
when there are multiple nodes with the same key.

Closes #1358

Multi handles repeatedly invert the queue of pending easy handles when
used with CURLMOPT_MAX_TOTAL_CONNECTIONS. This is caused by a multistep
process involving Curl_splaygetbest and violates the FIFO property of
the multi handle.
This patch fixes this issue by redefining the "best" node in the
context of timeouts as the "smallest not larger than now", and
implementing the necessary data structure modifications to do this
effectively, namely:
 - splay nodes with the same key are now stored in a doubly-linked
   circular list instead of a non-circular one to enable O(1)
   insertion to the tail of the list
 - Curl_splayinsert inserts nodes with the same key to the tail of
   the same list
 - in case of multiple nodes with the same key, the one on the head of
   the list gets selected

... by explicitly calling the ANSI versions of Windows API functions where
required.

struct mechtable is only used locally here. It can be declared static.

- Don't free postponed data on a connection that will be reused since
  doing so can cause data loss when pipelining.

Only Windows builds are affected by this.

Closes https://github.com/curl/curl/issues/1380