[4.0.x] build fails (module imap) with libcurl 7.29.0

[Arran Cudbard-Bell]

> On Jun 27, 2020, at 3:10 PM, Alan DeKok <aland at deployingradius.com> wrote:
> 
> On Jun 27, 2020, at 3:15 PM, Chaigneau, Nicolas via Freeradius-Devel <freeradius-devel at lists.freeradius.org> wrote:
>> 
>> Module imap is trying to use CURLOPT_DEFAULT_PROTOCOL, which was added in libcurl 7.45.0.
> 
>  I've pushed a fix, thanks.

It's an enumeration value not a macro so using ifdef doesn't work.

Curl helpfully provides:

https://github.com/curl/curl/blob/7f40633422df36b50e752749fb8795cac3e99e37/docs/libcurl/symbols-in-versions

and:

#if CURL_AT_LEASE_VERSION(x, y, x)

As the lack of CURLOPT_DEFAULT_PROTOCOL means that users must explicitly specify the scheme for curl based modules, and as I really don't feel like sticking #ifdefs everywhere in the code and using our own custom function to emulate this behaviour, I've bumped the minimum curl version to 7.45.0.

curl version 7.45.0 was released on October 7 2015.

If you don't need any of the libcurl based modules like rlm_rest or rlm_imap then they'll just be excluded from the build.

-Arran