Function normalize_environment 

pub fn normalize_environment(env: &mut BuildEnvironment)

Normalize a build environment for reproducibility.

• Sets SOURCE_DATE_EPOCH to “0” to eliminate timestamp variation
• Removes locale-dependent variables (LC_ALL, LANG, LANGUAGE) and sets them to “C” for deterministic collation
• Sets TZ=UTC for timezone consistency
• Canonicalizes paths by stripping trailing slashes and collapsing double slashes