86Box nightly – autobuild-f7fb9e3

Fix build errors after upstream merge

Add missing global variable declarations for turbo mode and virtualized CPU features:
- turbo_mode: Run emulator at maximum speed
- turbo_slow_cycles: Cycle skip count when turbo is off
- turbo_batch_ms: Turbo batch size in ms (0=auto, -1=unlimited)
- virtualized_cpu: Use virtualized CPU when allowed

Also remove duplicate force_constant_mouse declaration (already defined in mouse.c).

These variables were referenced in config.c and Qt UI code but were missing
their definitions after the upstream merge, causing linker errors.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>