thing-flinger has some hard-coded assumptions that are not universally true

• The assumption that rustup modified $HOME/.profile is not universal; I think this is dependent on how the remote machine installed rust:
  https://github.com/oxidecomputer/omicron/blob/2103a5f8bfe2ea03a272db92651b01bd1a1c972f/package/src/bin/thing-flinger.rs#L527-L529

• The "build", "package", and "check" commands attempt to perform a git checkout - I don't think we should assume that the remote filesystem is a git repository (it doesn't seem necessary here, and modifying which commit a user is operating on as a part of their build process seems bug-prone). As an example, I have traditionally rsync'd all files except my .git repository when developing between multiple machines.

https://github.com/oxidecomputer/omicron/blob/2103a5f8bfe2ea03a272db92651b01bd1a1c972f/package/src/bin/thing-flinger.rs#L198

https://github.com/oxidecomputer/omicron/blob/2103a5f8bfe2ea03a272db92651b01bd1a1c972f/package/src/bin/thing-flinger.rs#L222

https://github.com/oxidecomputer/omicron/blob/2103a5f8bfe2ea03a272db92651b01bd1a1c972f/package/src/bin/thing-flinger.rs#L239

• The choice of "debug" seems hardcoded in several spots (see: target/debug vs target/release) - it would be nice to have this be configurable

Start in package/src/bin/thing-flinger.rs, inspecting the rustup profile handling around lines 527-529, the git checkout operations around lines 198, 222, and 239, and the hard-coded debug paths. Trace the build, package, and check commands first. Done means these commands no longer rely on those remote-environment assumptions and the debug/release choice is configurable.