They need to be removed from the socket hash linked list with more care.

When sh_delentry() is called to remove a sockethash entry, remove all
individual transfers from the list first. To enable this, each Curl_easy struct
now stores a pointer to the sockethash entry to know how to remove itself.

Reported-by: Tom van der Woerdt and Kunal Ekawde

Fixes #3952
Fixes #3904
Closes #3953

Microsoft added support for Unix Domain Sockets in Windows 10 1803
(RS4). Rather than expect the user to enable Unix Domain Sockets by
uncommenting the #define that was added in 0fd6221f we use the RS4
pre-processor variable that is present in newer versions of the
Windows SDK.

Closes #3939

Closes #3945

Add the proxy and haproxy keywords in order to be able to exclude or
run these specific tests.

Closes https://github.com/curl/curl/pull/3949

Closes #3948

Closes #3916

- Revert all commits related to the SASL authzid feature since the next
  release will be a patch release, 7.65.1.

Prior to this change CURLOPT_SASL_AUTHZID  / --sasl-authzid was destined
for the next release, assuming it would be a feature release 7.66.0.
However instead the next release will be a patch release, 7.65.1 and
will not contain any new features.

After the patch release after the reverted commits can be restored by
using cherry-pick:

git cherry-pick a14d72ca a9499ff1 8c1cc369 c2a8d52a 0edf6907

Details for all reverted commits:

Revert "os400: take care of CURLOPT_SASL_AUTHZID in curl_easy_setopt_ccsid()."

This reverts commit 0edf6907.

Revert "tests: Fix the line endings for the SASL alt-auth tests"

This reverts commit c2a8d52a.

Revert "examples: Added SASL PLAIN authorisation identity (authzid) examples"

This reverts commit 8c1cc369.

Revert "curl: --sasl-authzid added to support CURLOPT_SASL_AUTHZID from the tool"

This reverts commit a9499ff1.

Revert "sasl: Implement SASL authorisation identity via CURLOPT_SASL_AUTHZID"

This reverts commit a14d72ca.

Closes #3937

Reported-by: smuellerDD on github
Fixes #3932
Closes #3933

Reported-by: Marcel Raad
Fixes #3926
Closes #3929

Closes #3930

Using the memdebug.h mem-leak feature, I noticed 2 calls like:
  FILE tool_parsecfg.c:70 fopen("c:\Users\Gisle\AppData\Roaming\_curlrc","rt")
  FILE tool_parsecfg.c:114 fopen("c:\Users\Gisle\AppData\Roaming\_curlrc","rt") 

No need for 'fopen(), 'fclose()' and a 'fopen()' yet again.

Reported-by: elsamuko at github
Fixes #3921
Closes #3922

Closes https://github.com/curl/curl/pull/3923

- Change data and protocol sections to CRLF line endings.

Prior to this change the tests would fail or hang, which is because
certain sections such as protocol require CRLF line endings.

Follow-up to a9499ff1 from today which added the tests.

Ref: https://github.com/curl/curl/pull/3790

Regression since e91e4816.

Reported-by: Tom Greenslade
Fixes #3924
Closes #3925

This reverts commit 3b06e68b.

Clearly this change wasn't good enough as it broke CURLOPT_LOW_SPEED_LIMIT +
CURLOPT_LOW_SPEED_TIME

Reported-by: Dave Reisner

Fixes #3927
Closes #3928

Added the ability for the calling program to specify the authorisation
identity (authzid), the identity to act as, in addition to the
authentication identity (authcid) and password when using SASL PLAIN
authentication.

Fixed #3653
Closes #3790

Testing against OpenSSH for Windows requires v7.7.0.0 or newer
due to the use of AllowUsers and DenyUsers. For more info see:
https://github.com/PowerShell/Win32-OpenSSH/wiki/sshd_config

Closes https://github.com/curl/curl/pull/3919

Closes https://github.com/curl/curl/pull/3919

Closes https://github.com/curl/curl/pull/3919

Closes https://github.com/curl/curl/pull/3919

Closes https://github.com/curl/curl/pull/3919

Also removed mentions from most docs.

Discussed: https://curl.haxx.se/mail/lib-2019-05/0045.html

Closes #3888

- adds the check to cmake

- fixes the configure check to work for cross-compiled windows builds

Closes #3917

If the proxy string is given as an IPv6 numerical address with a zone
id, make sure to use that for the connect to the proxy.

Reported-by: Edmond Yu

Fixes #3482
Closes #3918

Reported-by: GitYuanQu on github
Fixes #3902
Closes #3914

Made detection macros for these two functions in the same style as other
functions possibly in winsock in the hope this will work better to
detect these functions when cross-compiling for Windows.

Follow-up to e91e4816

Fixes #3913
Closes #3915