Mingw compilation fixes

Resolves: none, just an attempt to make audacium compile on mingw

note : The code does not compile on mingw yet. I opened this pull request to get some expert opinion on how to get it compiled.

[ ] I made sure the code compiles on my machine.
[x] I made sure there are no unnecessary changes in the code.
[x] I made sure the title of the PR reflects the core meaning of the issue you are solving.
[x] I made sure the commit message(s) contain a description and answer the question "Why do those changes fix that particular issue?" or "Why are those changes really necessary as improvements?".
[x] I hereby reaffirm that I am licensing my contribution under the GNU General Public License v2.0 or later (GPL-2.0-or-later).

Audacium / audacium