System Information
Win 7 x64

Blender Version
Broken: git
Worked: unknown

Short description of error
When built as a Python module, Blender overwrites sys.exit() codes with its own exit code.

Exact steps for others to reproduce the error

1. Import Blender as a Python module into an interactive Python console
2. Execute sys.exit(1)
3. Observe the exit code received by the OS, which will be 0

This bug can be worked around by calling os._exit() instead, which terminates the process immediately. That's hardly ideal though!