Original is deprecated. No idea if this version is actually the latest commit on master (it wasn't properly tagged) but I assume it is.
There's a chance the source code here doesn't even include the latest changes.
This wasn't compiled myself. This is just the binary package I got from Nuget:
https://www.nuget.org/packages/ilmerge/
https://nuget.info/packages/ILMerge/3.0.41