... 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

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"

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

Closes #1946

... 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.

Include a guide to form/mime API conversion.

Closes #1922

Closes #1921

- Use spaces instead of tabs as the delimiter.

Follow up to 7c52b12d which added the entry. The entry had used tabs but
the symbol-scan parser doesn't recognize tabs and would fail the symbol.

...fixup from b8e0fe19

... it just returns error:

Bug: https://github.com/curl/curl/commit/1328f69d53f2f2e937696ea954c480412b018451#commitcomment-24470367
Reported-by: Marcel Raad

Closes #1906

Also suppress length argument of curl_mime_name() (names are always
zero-terminated).

Otherwise, typecheck-gcc.h warns on MinGW-w64.

CA path processing was implemented when mbedtls.c was added to libcurl
in fe7590f7, but it was never enabled.

Bug: https://github.com/curl/curl/issues/1877


Reported-by:  <SBKarr@users.noreply.github.com>

It has already been fixed in 6140dfcf

curl_mime_encoder() is operational and documented.
curl tool -F option is extended with ";encoder=".
curl tool --libcurl option generates calls to curl_mime_encoder().
New encoder tests 648 & 649.
Test 1404 extended with an encoder specification.

and some minor whitespace fixes

... since people copy and paste code from this example and thus they get
an inefficient POST operation without a good reason and sometimes
without understanding why.

Instead this now returns as much data as possible.