... because otherwise not everything get closed down correctly.

Fixes #2708
Closes #2712

Closes #2713

Closes #2706

Closes #2704

telnet.c(1401,28): warning: cast from function call of type 'int' to
non-matching type 'HANDLE' (aka 'void *') [-Wbad-function-cast]

Fixes #2696
Closes #2700

Closes #2698

The code treated the set version as the *exact* version to require in
the TLS handshake, which is not what other TLS backends do and probably
not what most people expect either.

Reported-by: Andreas Olsson
Assisted-by: Gaurav Malhotra
Fixes #2691
Closes #2694

Reported-by: Andreas Olsson
Fixes #2692
Closes #2693

The previous example was a little bit confusing, because SSL* structure
(or other "in use" SSL connection pointer) is not accessible after the
transfer is completed, therefore working with the raw TLS library
specific pointer needs to be done during transfer.

Closes #2690

... since default uses the threaded one and we test the c-ares build
already.

Closes #2689

Since it isn't used either and requires the getnameinfo check

Follow-up to 0aeca417

Closes #2687

... and trim the threaded Curl_resolver_getsock() to return zero
millisecond wait times during the first three milliseconds so that
localhost or names in the OS resolver cache gets detected and used
faster.

Closes #2685

The linker is pretty dumb and processes things left to right, keeping a
tally of symbols it hasn't resolved yet. So, we need -ldl to appear
after -lcrypto otherwise the linker won't find the dl functions.

Closes #2684

... it was previously unchecked in two places and thus errors could
remain undetected and cause trouble.

Closes #2681

Follow-up to b6a16afa

... to work with longer passwords etc. Grow it from a 256 to a 4096
bytes buffer.

Reported-by: Dario Nieuwenhuis
Fixes #2676
Closes #2680

Closes #2673

Fixes #2677
Closes #2679

Follow-up to 2c15693a.

Bug #2674
Closes #2675

Bug: https://curl.haxx.se/mail/lib-2018-06/0100.html

This will make possible to select the SSL backend (using
curl_global_sslset()) even when the libcurl is built using CMake

Closes #2665

By masking sure to use the *current* easy handle with extracted
connections from the cache, and make sure to NULLify the ->data pointer
when the connection is put into the cache to make this mistake easier to
detect in the future.

Reported-by: Will Dietz
Fixes #2669
Closes #2672

... run a few more tortured based and run all tests event-based.

Closes #2664

When the application just started the transfer and then stops it while
the name resolve in the background thread hasn't completed, we need to
wait for the resolve to complete and then cleanup data accordingly.

Enabled test 1553 again and added test 1590 to also check when the host
name resolves successfully.

Detected by OSS-fuzz.
Closes #1968

Ref: https://github.com/curl/curl/pull/2660

Closes https://github.com/curl/curl/pull/2662