ERR_error_string with NULL parameter is not thread-safe. The library
writes the string into some static buffer. Two threads doing this at
once may clobber each other and run into problems. Switch to
ERR_error_string_n which avoids this problem and is explicitly
bounds-checked.

Also clean up some remnants of OpenSSL 0.9.5 around here. A number of
comments (fixed buffer size, explaining that ERR_error_string_n was
added in a particular version) date to when ossl_strerror tried to
support pre-ERR_error_string_n OpenSSLs.

Closes #1424

Rather than making assumptions about the values, use a switch-case.

Closes #1424

A few random typos, and minor whitespace cleanups, found in comments
while reading code.

Closes #1423

This makes test 1135 pass with CRLF checkouts.

Ref: https://github.com/curl/curl/pull/1344#issuecomment-289243166
Closes https://github.com/curl/curl/pull/1422

Ignore everything after the version numbers in LIBCURL_VERSION and
LIBCURL_VERSION_NUM to ged rid of the extra CR character.
This makes tests 1022 and 1023 pass on Linux with a CRLF checkout.

Ref: https://github.com/curl/curl/pull/1344#issuecomment-289243166
Closes https://github.com/curl/curl/pull/1422

Bash on Linux errors out on CR characters.
This makes tests 1221 and 1222 pass on Linux with a CRLF checkout.

Ref: https://github.com/curl/curl/pull/1344#issuecomment-289243166
Closes https://github.com/curl/curl/pull/1422

MinGW-w64 complains:
warning: conversion to 'long int' from 'time_t {aka long long int}' may
alter its value [-Wconversion]
Fix this by using the correct type.

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