Allow FPM to be loaded from a environment variable.

[cwood]

I have a use case where I want to do a monorepo and have separate subdirectories.

An example: a/.fpm b/.fpm .fpm

I want to be able to have a global .fpm for my monorepo and have each service specify there own .fpms to be added.

I expect the run to look like FPMRC=a fpm ...

Hopefully, this will resolve that. Let me know what else needs to be done.

[bartclone]

Nice idea! However, what's the addition here, besides looping through the directories? Maybe you can provide a somewhat full(er) example FPMRC-file?