Follow up to 7fe81ec2: make sure 'host' is either NULL or malloced.

Fixes #1255

Reported-by: Dan Fandrich
Bug: https://curl.haxx.se/mail/lib-2017-02/0032.html

When removing an easy handler from a multi before it completed its
transfer, and it had pushed streams, it would segfault due to the pushed
counted not being cleared.

Fixed-by:  <zelinchen@users.noreply.github.com>
Fixes #1249

Using sftp to delete a file with CURLOPT_NOBODY set with a reused
connection would fail as curl expected to get some data. Thus it would
retry the command again which fails as the file has already been
deleted.

Fixes #1243

Ref: https://github.com/curl/curl/pull/1245

Closes https://github.com/curl/curl/pull/1245

The information extracted from the server certificates in step 3 is only
used when in verbose mode, and there is no error handling or validation
performed as that has already been done. Only run the certificate
information extraction when in verbose mode and libcurl was built with
verbose strings.

Closes https://github.com/curl/curl/pull/1246

- Remove the SNI disabled when host verification disabled message
  since that is incorrect.

- Show a message for legacy versions of Windows <= XP that connections
  may fail since those versions of WinSSL lack SNI, algorithms, etc.

Bug: https://github.com/curl/curl/pull/1240

This is the previously manually edited changelog, not touched since Aug
2015. Still present in git for those who wants it.

Ref: https://sourceforge.net/blog/introducing-https-for-project-websites/
Closes: https://github.com/curl/curl/pull/1247

- Document HTTPS proxy type.

- Document --write-out %{proxy_ssl_verify_result}.

- Document SOCKS proxy + HTTP/HTTPS proxy combination.

HTTPS proxy support was added in 7.52.0 for OpenSSL, GnuTLS and NSS.

Ref: https://github.com/curl/curl/commit/cb4e2be

- s/CURLOPT_SOCKS_PROXY/CURLOPT_PRE_PROXY
  Follow-up to 7907a2be and 845522ca.

- Fix incorrect id for CURLOPT_PROXY_PINNEDPUBLICKEY.

- Add id for CURLOPT_ABSTRACT_UNIX_SOCKET.

Bug: https://github.com/curl/curl/issues/1237


Reported-by:  <jonrumsey@users.noreply.github.com>

- Test for and set HAVE_FSETXATTR when support for extended file
  attributes is present.

Closes https://github.com/curl/curl/pull/1176

SSL_CTX_add_extra_chain_cert takes ownership of the given certificate
while, despite the similar name, SSL_CTX_add_client_CA does not. Thus
it's best to call SSL_CTX_add_client_CA before
SSL_CTX_add_extra_chain_cert, while the code still has ownership of the
argument.

Closes https://github.com/curl/curl/pull/1236

closes #1227

... refer to the web site for the web versions.

Closes #1231

SSL session reuse with TLS session tickets is not supported yet.
Use SSL session IDs instead.

See https://github.com/curl/curl/issues/1109

SSL session reuse with TLS session tickets is not supported yet.
Use SSL session IDs instead.

Fixes https://github.com/curl/curl/issues/1109

This bugfix is similar to commit c111178b.

This repairs cookies for localhost.

Non-PSL builds will now only accept "localhost" without dots, while PSL
builds okeys everything not listed as PSL.

Added test 1258 to verify.

This was a regression brought in a76825a5

Support is trickling in already.

Closes #1226

Thumbs-up-by: Jay Satiro

Closes #1225

The winbuild/ build files is now the single MSVC makefile build choice.

Closes #1215

On Windows it's possible to have input files with CRLF line endings and
a perl that defaults to LF line endings (eg msysgit). Currently that
results in generator output of mixed line endings of CR, LF and CRLF.

This change fixes that issue in the most succinct way by opening the
files in :crlf text mode even when the perl being used does not default
to that mode. (On operating systems that don't have a separate text mode
it's essentially a no-op.) The output continues to be in the perl's
native line ending.

A regression brought in cb4e2be7

Reported-by: Michael Kaufmann
Bug: https://github.com/curl/curl/issues/1174#issuecomment-274018791

When using multi, mbedtls handshake is in non blocking mode.  vtls must
set wait for read/write flags for the socket.

Closes #1223

Replace use of fixed macro BUFSIZE to define the size of the receive
buffer.  Reappropriate CURLOPT_BUFFERSIZE to include enlarging receive
buffer size.  Upon setting, resize buffer if larger than the current
default size up to a MAX_BUFSIZE (512KB). This can benefit protocols
like SFTP.

Closes #1222