I opened a PR adding mingw subpackages to libsodium according to my best knowledge (which is not too large related to mingw packaging): https://src.fedoraproject.org/rpms/libsodium/pull-request/3
I talked with the maintainer and it could be accepted, but I would like someone more experienced from https://fedoraproject.org/wiki/MinGW to take a look and tell me if i missed some simplifications.
Thanks.