The function only exists since nghttp2 1.12.0.

Bug: https://github.com/curl/curl/commit/a4d8888#commitcomment-19985676
Reported-by: Michael Kaufmann

Closes #1125

Now all options are in the new system.

Moved over to the new format

There's mostly likely no need to allow setting SSLv2/3 version for HTTPS
proxy. Those protocols are insecure by design and deprecated.

Also define it in ILE/RPG binding.

Closes #1142

Add missing tests for CURLINFO_SCHEME, CURLINFO_PROTOCOL, %{scheme},
and %{http_version}

closes #1143

Follow-up to 4f8b1774

Sorted the lists too.

... and include the new ones in the PDF and HTML generation targets

Closes #1141

Prior to this change we depended on errno if strtol could not perform a
conversion. POSIX says EINVAL *may* be set. Some implementations like
Microsoft's will not set it if there's no conversion.

Ref: https://github.com/curl/curl/commit/ee4f7660#commitcomment-19658189

Ref: https://github.com/curl/curl/pull/1064#issuecomment-260052409

Follow-up to dbadaebf which changed the style.

- Restore the removed parts of the parameter check.

Follow-up to 945f60e8 which altered the parameter check.

Adds access to the effectively used protocol/scheme to both libcurl and
curl, both in string and numeric (CURLPROTO_*) form.

Note that the string form will be uppercase, as it is just the internal
string.

As these strings are declared internally as const, and all other strings
returned by curl_easy_getinfo() are de-facto const as well, string
handling in getinfo.c got const-ified.

Closes #1137

Detects (char*) and 'char*foo' uses.

Verifies a 'char *name' style, with no space after the asterisk.

Coverity CID 1394666

It builds and runs all test cases. No adaptations for actual HTTPS proxy
support has been made.

vtls/gtls.c: In function ‘Curl_gtls_data_pending’:
vtls/gtls.c:1429:3: error: this ‘if’ clause does not guard... [-Werror=misleading-indentation]
   if(conn->proxy_ssl[connindex].session &&
      ^~
      vtls/gtls.c:1433:5: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘if’
           return res;