claws-mail 3.17.4_4 fails to build because configure can't find libetpan

[m5comp]

The newest version of claws-mail doesn't build because of this error in configure:

checking whether to use libetpan... yes
checking for libetpan-config... no

I have libetpan installed, so I don't know why configure can't find it. I am running macOS 10.15.1 and have Xcode 11.2 installed.

[mf2k (Frank Schima)]

In the future, please add the port maintainer(s) to Cc (port info --maintainers claws-mail), if any.

[pmetzger (Perry E. Metzger)]

This is almost certainly my fault; I'll figure it out.

[pmetzger (Perry E. Metzger)]

Okay, the problem is that the latest version of libetpan, even though it only bumped a patch number, switched to pkg-config. A patch is needed for claws-mail to use pkg-config to find out if libetpan is installed; that will require hacking configure.ac to use pkg-config instead of the current mechanism. Unfortunately I'm kind of ill right now and have never done this before so I can't get to it tonight. However, if you need to brute force it, that's the place to do it.

[pmetzger (Perry E. Metzger)]

Okay, as of now, this should be working; I added a patch from one of the developers to eal with the latest libetpan.