What to do with binaries?
Gentoo Mono Handbook
DISTDIR is supposed to contain source build artefacts.
external .nuget packages (from nuget.org) are ready-made items and not used in the build process as sources
It is possible to create another directory to download binary files.
addwrite
for sandbox:
https://devmanual.gentoo.org/function-reference/sandbox-functions/index.html
https://devmanual.gentoo.org/appendices/common-problems/index.html
https://devmanual.gentoo.org/general-concepts/sandbox/index.html
