Test 1422 updated to verify.

Closes #1964

This allows freeing a mime structure bound to the easy handle before
curl_easy_cleanup().

Fixes #1970.

... like a very large non-existing RTSP version number.

Added test 577 to verify.

Detected by OSS-fuzz.
Closes #1969

Reported-by: Alexey Melnichuk
Fixes #1962

Also avoid dangling pointers in referencing parts.

This reverts commit f3e03f6c.

Caused memory leaks in the fuzzer, needs to be done differently.

Disable test 1553 for now too, as it causes memory leaks without this
commit!

Closes #1960

... as we must clean up memory.

When imap_done() got called before a connection is setup, it would try
to "finish up" and dereffed a NULL pointer.

Test case 1553 managed to reproduce. I had to actually use a host name
to try to resolve to slow it down, as using the normal local server IP
will make libcurl get a connection in the first curl_multi_perform()
loop and then the bug doesn't trigger.

Fixes #1953
Assisted-by: Max Dymond

These are around 5% flaky in my Linux x86 autobuilds.

When CURL_DISABLE_CRYPTO_AUTH is defined, Curl_none_md5sum's parameters
are not used.

... fixes a memory leak with at least IMAP when remove_handle is never
called and the transfer is abruptly just abandoned early.

Test 1552 added to verify

Detected by OSS-fuzz
Assisted-by: Max Dymond
Closes #1954

Fixes #1950: curlx_strtoofft() doesn't fully protect against null 'str'
argument.

Closes #1952

Reported-by: Javier Sixto
Fixes #1955
Closes #1956

The source code is now prepared to handle the case when both
Win32 Crypto and OpenSSL/NSS crypto backends are enabled
at the same time, making it now possible to enable `USE_WIN32_CRYPTO`
whenever the targeted Windows version supports it. Since this
matches the minimum Windows version supported by curl
(Windows 2000), enable it unconditionally for the Win32 platform.

This in turn enables SMB (and SMBS) protocol support whenever
Win32 Crypto is available, regardless of what other crypto backends
are enabled.

Ref: https://github.com/curl/curl/pull/1840#issuecomment-325682052

Closes https://github.com/curl/curl/pull/1943

Reported-by: Wyatt O'Day
Fixes #1945
Closes #1947

Closes https://github.com/curl/curl/pull/1794

Closes #1946

- New `CURL_DLL_SUFFIX` envvar will add a suffix to the generated
  libcurl dll name. Useful to add `-x64` to 64-bit builds so that
  it can live in the same directory as the 32-bit one. By default
  this is empty.

- New `CURL_DLL_A_SUFFIX` envvar to customize the suffix of the
  generated import library (implib) for libcurl .dll. It defaults
  to `dll`, and it's useful to modify that to `.dll` to have the
  standard naming scheme for mingw-built .dlls, i.e. `libcurl.dll.a`.

Closes https://github.com/curl/curl/pull/1942

Use the external curl-fuzzer repository for fuzzing.

Closes #1923

Closes #1936

Closes #1939

Ref: https://github.com/curl/curl/issues/1002

Compare these settings in Curl_ssl_config_matches():
- verifystatus (CURLOPT_SSL_VERIFYSTATUS)
- random_file (CURLOPT_RANDOM_FILE)
- egdsocket (CURLOPT_EGDSOCKET)

Also copy the setting "verifystatus" in Curl_clone_primary_ssl_config(),
and copy the setting "sessionid" unconditionally.

This means that reusing connections that are secured with a client
certificate is now possible, and the statement "TLS session resumption
is disabled when a client certificate is used" in the old advisory at
https://curl.haxx.se/docs/adv_20170419.html is obsolete.

Reviewed-by: Daniel Stenberg

Closes #1917

Reviewed-by: Daniel Stenberg

Closes #1919

... now with a -formadd suffix. While the new mime API is introduced in
7.56.0 we must acknowledge that lots of users can't upgrade their curl
versions immediately.

... a single double quote could leave the entry path buffer without a zero
terminating byte. CVE-2017-1000254

Test 1152 added to verify.

Reported-by: Max Dymond
Bug: https://curl.haxx.se/docs/adv_20171004.html