Stick to "Schannel" everywhere - follow up to 180501cb.

This fixes GSSAPI builds with the libraries in a non-standard location.
The testing for recv() were failing because it failed to link
the Kerberos libraries, which are not needed for this or subsequent
tests.

fixes #3743
closes #3744

With CMAKE_TRY_COMPILE_TARGET_TYPE set to STATIC_LIBRARY, the try_compile()
(which is used by check_c_source_compiles()) will build static library
instead of executable. This avoids linking additional libraries in and thus
speeds up those checks a little.

This commit also avoids #3743 (GSSAPI build errors) on itself with cmake
3.6 or above. That issue was fixed separately for all versions.

Ref: #3744

- Remove nneeded include_regular_expression.
  It was setting what is already a default.

- Remove duplicated include.

- Don't check for pre-3.0.0 CMake version.
  We already require at least 3.0.0, so it's just clutter.

Ref: #3744

Should the parent environment set this variable then the build might
not be performed as the user intended.

Fixes #3738
Closes #3749

bumped to 7.65.0 for next release

bytes... since the protocol needs to store the length in a single byte field.

Reported-by: XmiliaH on github
Fixes #3737
Closes #3740

fixes #3741
Closes #3742

Fixes #3745
Closes #3746

The following snippet
```

int main()
{
    CURL* hCurlHandle = curl_easy_init();
    curl_easy_setopt(hCurlHandle, CURLOPT_URL, "http://example.com");
    curl_easy_setopt(hCurlHandle, CURLOPT_PROXY, "1");
    curl_easy_perform(hCurlHandle);
    curl_easy_cleanup(hCurlHandle);
    return 0;
}
```
triggers the following Valgrind warning

```
==4125== Invalid read of size 8
==4125==    at 0x4E7D1EE: Curl_llist_remove (llist.c:97)
==4125==    by 0x4E7EF5C: detach_connnection (multi.c:798)
==4125==    by 0x4E80545: multi_runsingle (multi.c:1451)
==4125==    by 0x4E8197C: curl_multi_perform (multi.c:2072)
==4125==    by 0x4E766A0: easy_transfer (easy.c:625)
==4125==    by 0x4E76915: easy_perform (easy.c:719)
==4125==    by 0x4E7697C: curl_easy_perform (easy.c:738)
==4125==    by 0x4008BE: main (in /home/even/curl/test)
==4125==  Address 0x9b3d1d0 is 1,120 bytes inside a block of size 1,600 free'd
==4125==    at 0x4C2ECF0: free (vg_replace_malloc.c:530)
==4125==    by 0x4E62C36: conn_free (url.c:756)
==4125==    by 0x4E62D34: Curl_disconnect (url.c:818)
==4125==    by 0x4E48DF9: Curl_once_resolved (hostip.c:1097)
==4125==    by 0x4E8052D: multi_runsingle (multi.c:1446)
==4125==    by 0x4E8197C: curl_multi_perform (multi.c:2072)
==4125==    by 0x4E766A0: easy_transfer (easy.c:625)
==4125==    by 0x4E76915: easy_perform (easy.c:719)
==4125==    by 0x4E7697C: curl_easy_perform (easy.c:738)
==4125==    by 0x4008BE: main (in /home/even/curl/test)
==4125==  Block was alloc'd at
==4125==    at 0x4C2F988: calloc (vg_replace_malloc.c:711)
==4125==    by 0x4E6438E: allocate_conn (url.c:1654)
==4125==    by 0x4E685B4: create_conn (url.c:3496)
==4125==    by 0x4E6968F: Curl_connect (url.c:4023)
==4125==    by 0x4E802E7: multi_runsingle (multi.c:1368)
==4125==    by 0x4E8197C: curl_multi_perform (multi.c:2072)
==4125==    by 0x4E766A0: easy_transfer (easy.c:625)
==4125==    by 0x4E76915: easy_perform (easy.c:719)
==4125==    by 0x4E7697C: curl_easy_perform (easy.c:738)
==4125==    by 0x4008BE: main (in /home/even/curl/test)
```

This has been bisected to commit 2f44e94e

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=14109
Credit to OSS Fuzz

As previously planned and documented in DEPRECATE.md, all pipelining
code is removed.

Closes #3651

Closes #3731
Fixes #3289

This groups all SSL backends into the feature "SSL" and sets the
SSL_BACKENDS analogue to configure.ac

Closes https://github.com/curl/curl/pull/3736

In case of an empty list, SORTing leads to the cmake error "list
sub-command SORT requires list to be present."

Closes https://github.com/curl/curl/pull/3736

Fish defines a vendor completions directory for completions that are not
installed as part of the fish project itself, and the vendor completions
are preferred if they exist. This prevents trying to overwrite the
builtin curl.fish completion (or creating file conflicts in distro
packaging).

Prefer the pkg-config defined location exported by fish, if it can be
found, and fall back to the correct directory defined by most systems.

Closes #3723
Reviewed-by: Daniel Gustafsson

Removing the block is consistent with line 954/957.

Closes https://github.com/curl/curl/pull/3732

Just remove the redundant condition, which also makes it clear that
k->buf is always 0-terminated if this break is not hit.

Closes https://github.com/curl/curl/pull/3732

- Fix clang string-plus-int warning.

Clang 8 warns about adding a string to an int does not append to the
string. Indeed it doesn't, but that was not the intention either. Use
array indexing as suggested to silence the warning. There should be no
functional changes.

(In other words clang warns about "foo"+2 but not &"foo"[2] so use the
latter.)

smtp.c:1221:29: warning: adding 'int' to a string does not append to the
string [-Wstring-plus-int]
      eob = strdup(SMTP_EOB + 2);
            ~~~~~~~~~~~~~~~~^~~~

Closes https://github.com/curl/curl/pull/3729

All Windows APIs have been natively UTF-16 since Windows 2000 and the
non-Unicode variants are just wrappers around them. Only Windows 9x
doesn't understand Unicode without the UnicoWS DLL. As later Visual
Studio versions cannot target Windows 9x anyway, using the ANSI API
doesn't really have any benefit there.

This avoids issues like KNOWN_BUGS 6.5.

Ref: https://github.com/curl/curl/issues/2120
Closes https://github.com/curl/curl/pull/3720

Bump the version in progress to 7.64.2, if we merge any "change"
before the cut-off date we can update the version.

Closes #3724
Reviewed-by: Jakub Zakrzewski
Reviewed-by: Daniel Gustafsson

OAUTHBEARER tokens were incorrectly generated in a format similar to
XOAUTH2 tokens. These changes make OAUTHBEARER tokens conform to the
RFC7628.

Fixes: #2487
Reported-by: Paolo Mossino

Closes https://github.com/curl/curl/pull/3377

Commit f5bc578f reintroduced the
warning fixed in commit 2f5f31bb.
Extend fhnd's scope and reuse that variable instead of calling
_get_osfhandle a second time to fix the warning again.

Closes https://github.com/curl/curl/pull/3718

Already done in commit d5cfefd0 for the
library project, but I forgot the tool project template. Now also
removed for that.

Try to run as many test cases as possible on each OS version.
12.0 passes 13 more tests than the older versions, so we might as well
run them.

Reported-by: Wyatt O'Day
Fixes #3715
Closes #3716

This allows a way to test changes other than through PRs.

Closes #3699

Make sure to downgrade to 1.1 even when we get this HTTP/2 stream error
on first flight.

Reported-by: niner on github
Fixes #3696
Closes #3707