Just to know: were you not able to find aMule 2.3.1 packages with UPnP enabled?
You could try some of packages from my GDrive (warning: use them at your own risk, I just built them but I usually run some "development" version) at the following link
https://drive.google.com/drive/#folders/0Bx81ff2QeD0_aHhXblZkT09mZHc/0Bx81ff2QeD0_Z0l5WGZDNTFRZUEAs regards Yosemite: one annoying problem I found is the annoying message in console
15/03/15 12:19:45,324 amulegui[680]: WARNING: The Gestalt selector gestaltSystemVersion is returning 10.9.2 instead of 10.10.2. Use NSProcessInfo's operatingSystemVersion property to get correct system version number.
Call location:
This is due to wxWidgets and the use of a deprecated API: due to this API the OS version is incorrectly detected (the problem is the minor OS version: OS X Yosemite is the forst one to have a minor version with 2 cyphers instead of 1).
We need to wait for a fix from wxWidgets crew.
Bye,
Mr Hyde