Regression since commit 710f14ed.

Bug: https://github.com/curl/curl/issues/422
Reported-by: Justin Ehlert

..SH should be .SH

Bug: https://github.com/curl/curl/issues/705
Reported-by: Eric S. Raymond

Closes #658

Introducing a function for closing the secondary connection to make this
bug less likely to happen again.

Reported-by: daboul
Closes #701

I got a crash with this stack:

curl/lib/url.c:2873 (Curl_removeHandleFromPipeline)
curl/lib/url.c:2919 (Curl_getoff_all_pipelines)
curl/lib/multi.c:561 (curl_multi_remove_handle)
curl/lib/url.c:415 (Curl_close)
curl/lib/easy.c:859 (curl_easy_cleanup)

Closes #704

And delete trailing whitespace
And rename section 17 to "command line tool" from "client"

Closes #702

It also makes it less readable as plain text, so let's keep this
primarily for github use.

Removed the top ascii art logo, as it looks weird when markdownified.

Attempt to make it look more appealing on github

Fixed inconsistency from commit 1eae1140 and 0ad6c722 of the order
in which Perl was added to the PATH.

and removed erroneous reference to test case lib509

Since two of the cookies would now otherwise expire and cause the test
to fail after commit 20de9b4f

Discussed in #697

Bug: https://github.com/curl/curl/pull/693

Prior to this change when a single protocol CURL_SSLVERSION_ was
specified by the user that version was set only as the minimum version
but not as the maximum version as well.

In makefile.m32, option -ssh2 (libssh2) automatically implied -ssl
(OpenSSL) option, with no way to override it with -winssl. Since both
libssh2 and curl support using Windows's built-in SSL backend, modify
the logic to allow that combination.

Prior to this change cookies with an expiry date that failed parsing
and were converted to session cookies could be purged in remove_expired.

Bug: https://github.com/curl/curl/issues/697
Reported-by: Seth Mos

... as it was already checked previously within the function.

Reported-by: Dmitry-Me
Closes #695

Prevent a crash if 2 (or more) requests are made to the same host and
pipelining is enabled and the connection does not complete.

Bug: https://github.com/curl/curl/pull/690

using envvars `CURL_LDFLAG_EXTRAS_DLL` and
`CURL_LDFLAG_EXTRAS_EXE` respectively. This
is useful f.e. to pass ASLR-related extra
options, that are required to make this
feature work when using the mingw toolchain.

Ref: https://github.com/curl/curl/pull/670#issuecomment-190863985

Closes https://github.com/curl/curl/pull/689

Reported-by: Dmitry-Me
Fixes #688

The assignment of the mbedTLS TLS session info in the parent commit was
incorrect. Change the assignment to a pointer to the session structure.

.. and preprocessor check TLS session info is defined for all backends.

Some systems have special files that report as 0 bytes big, but still
contain data that can be read (for example /proc/cpuinfo on
Linux). Starting now, a zero byte size is considered "unknown" size and
will be read as far as possible anyway.

Reported-by: Jesse Tan

Closes #681

- Warn if --with-ca-bundle file does not exist.

- Warn if --with-ca-path directory does not contain certificates.

- Improve help messages for both.

Example configure output:

  ca cert bundle:   /some/file   (warning: certs not found)
  ca cert path:     /some/dir   (warning: certs not found)

Bug: https://github.com/curl/curl/issues/404
Reported-by: Jeffrey Walton

... as when pipelining is used, we read things into a unified buffer and
we don't do that with HTTP/2. This could then easily make programs that
set CURLMOPT_PIPELINING = CURLPIPE_HTTP1|CURLPIPE_MULTIPLEX to get data
intermixed or plain broken between HTTP/2 streams.

Reported-by: Anders Bakken