Build a sanitized environment object for spawning child processes. Merges base and overlay, drops undefined values, and handles platform-specific normalization (e.g. case-insensitivity on Windows).
base
overlay
Optional
Base environment (usually process.env).
process.env
Environment variables to overlay.
Build a sanitized environment object for spawning child processes. Merges
baseandoverlay, drops undefined values, and handles platform-specific normalization (e.g. case-insensitivity on Windows).