I have observed the following error on evergreen on osx:
bash: line 8: dos2unix: command not found
There is a comment above that point in .mci.yml indicating that the dos2unix command was only needed until this pull request was merged (which happened years ago):
https://github.com/mongodb-labs/drivers-evergreen-tools/pull/6
Investigate whether this command is still necessary, and how to avoid it on osx.