SAM Build: path is on mount 'D:', start on mount 'C:'

A toolkit user was having issues with SAM build when the target build directory and the code were on different drives (see https://github.com/aws/aws-toolkit-vscode/issues/2296). By default the toolkit will create a temporary directory to build in which happened to be on a different drive, so the solution was to manually specify one on the same drive.

The failure occurs here: https://github.com/aws/aws-sam-cli/blob/ec9f5d89971b823fa01071c96b7de90ea5e5303a/samcli/commands/_utils/template.py#L233

Is this an edge-case for windows machines that needs to be looked into? From what I understand relative paths between drives are impossible so cross-drive resolution would just always fail here.