Closes https://github.com/bagder/curl/pull/471

Closes https://github.com/bagder/curl/pull/459

... even for those that don't support providing anything in the
'internals' struct member since it offers a convenient way for
applications to figure this out.

Closes #449

Like for example brotli, as being implemented in Firefox now.

closes #443

Closes #334

CURLE_SSL_PINNEDPUBKEYNOTMATCH and CURLE_SSL_INVALIDCERTSTATUS

- Show how a certificate can be obtained using OpenSSL.

Bug: https://github.com/bagder/curl/pull/430
Reported-by: Daniel Hwang

s => is

Closes #428

long => double

If the port number in the proxy string ended weirdly or the number is
too large, skip it. Mostly as a means to bail out early if a "bare" IPv6
numerical address is used without enclosing brackets.

Also mention the bracket requirement for IPv6 numerical addresses to the
man page for CURLOPT_PROXY.

Closes #415

Reported-by: Marcel Raad

Closes #414
Closes #413

leavit => leaveit

closes #412

This reverts commit a60bde79 I have
pushed by mistake.  Apologies for my incompetent use of the git repo!

changed macro name, moved and renamed script to become docs/libcurl/has.pl,
generate code that is checksrc compliant

and some general cleaning up

- Warn that cookies without a domain are sent to any domain:
CURLOPT_COOKIELIST, CURLOPT_COOKIEFILE, --cookie

- Note that imported Set-Cookie cookies without a domain are no longer
exported:
CURLINFO_COOKIELIST, CURLOPT_COOKIEJAR, --cookie-jar

Put braces around empty "if" body in libcurl.m4 check to avoid warning:

        suggest braces around empty body in an 'if' statement

and make it work with -Werror builds.

Closes #402

Closes #398

remove redundant '}'