For those that build there own and want to play around with 3333's code here:
Simply download this diff file:
https://github.com/rinne1998/Sigil/c...429e7ac88.diff
To apply it (macOS and Linux)
cd Sigil/
patch -p1 < PATH_TO_DOWNLOADED_DIFF_FILE
And it should apply perfectly cleanly over current Sigil master and will build with no issues at all.
Give it a try.
PS. If you have patch.exe on your Windows box, the same things should work but otherwise if anyone knows the native Windows commands to apply a diff file, please post them here.