+GC_USE_GETWRITEWATCH=<n> - Only if MPROTECT_VDB and GWW_VDB are both defined
+ (Win32 only). Explicitly specify which strategy of
+ keeping track of dirtied pages should be used.
+ If n=0 then GetWriteWatch() is not used (falling back to
+ protecting pages and catching memory faults strategy)
+ else the collector tries to use GetWriteWatch-based
+ strategy (GWW_VDB) first if available.
+
+GC_DISABLE_INCREMENTAL - Ignore runtime requests to enable incremental GC.
+ Useful for debugging.
+