... filter early instead of risking "funny values" having to be dealt
with elsewhere.

... that are multiplied by 1000 when stored.

For 32 bit long systems, the max value accepted (2147483 seconds) is >
596 hours which is unlikely to ever be set by a legitimate application -
and previously it didn't work either, it just caused undefined behavior.

Also updated the man pages for these timeout options to mention the
return code.

Closes #1938

Allow to ovverride certain build tools, making it possible to
use LLVM/Clang to build curl. The default behavior is unchanged.
To build with clang (as offered by MSYS2), these settings can
be used:

CURL_CC=clang
CURL_AR=llvm-ar
CURL_RANLIB=llvm-ranlib

Closes https://github.com/curl/curl/pull/1993

Use memset() to initialize a structure to avoid LLVM/Clang warning:
ldap.c:193:39: warning: missing field 'UserLength' initializer [-Wmissing-field-initializers]

Closes https://github.com/curl/curl/pull/1992

NOTE: it makes them terribly slow. I recommend only using valgrind for
specific torture tests or using lots of patience.

... to allow them to be included in torture tests too.

closes #1980

... we used it only for the fuzzer, which we now have in a separate git
repo.

Closes #1990

Reported-by: Jeroen Ooms
Closes #1988

Include test cases in 554, 587, 650.

Fixes https://github.com/curl/curl/issues/1986

Closes PR https://github.com/curl/curl/pull/1985

If stdin is not a regular file, its content is memory-buffered to enable
a possible data "rewind".
In all cases, stdin data size is determined before real use to avoid
having an unknown part's size.

--libcurl generated code is left as an unbuffered stdin fread/fseek callback
part with unknown data size.

Buffering is not supported in deprecated curl_formadd() API.

following the new github "standard"

Now VERIFYHOST, VERIFYPEER and VERIFYSTATUS options change during active
connection updates the current connection's (i.e.'connectdata'
structure) appropriate ssl_config (and ssl_proxy_config) structures
variables, making these options effective for ongoing connection.

This functionality was available before and was broken by the
following change:
"proxy: Support HTTPS proxy and SOCKS+HTTP(s)"
CommitId: cb4e2be7.

Bug: https://github.com/curl/curl/issues/1941

Closes https://github.com/curl/curl/pull/1951

Those were temporary things we'd add and remove for our own convenience
long ago. The last few stayed around for too long as an oversight but
have since been removed. These days we have a running
BORINGSSL_API_VERSION counter which is bumped when we find it
convenient, but 2015-11-19 was quite some time ago, so just check
OPENSSL_IS_BORINGSSL.

Closes #1979

... as otherwise it could leak that memory.

Detected by OSS-fuzz:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=3600

Assisted-by: Max Dymond
Closes #1977

Reported-by: Zenju on github

Test 244 added to verify
Fixes #1974
Closes #1976

Ref: #1974

Enable PKCS12 for all non-boringssl builds without relying on configure
or cmake checks.

Bug: https://curl.haxx.se/mail/lib-2017-10/0007.html
Reported-by: Christian Schmitz
Closes #1948

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.