minor whitespace cleanups
whitespace cleanups
use more accurate typecast when pushing state
add debugging facility to determine memcell reachability
add check to ensure that gc_iterate is not called recursively
fix bug in memory_gc_advise_new_link where memcells could be accidentally moved to the free list even if they are still referenced
add optional checks to verify negative reachability when memcells are moved to new lists (GC_REACHABILITY_VERIFICATION)
add missing CLEAR_ON_FREE
minor refactoring of memory_gc_print_state to enable slightly more readable output
rename flags fields in memstate and memcell to be more difficult to confuse
add GC_REACHABILITY_VERIFICATION
reorganize CFLAGS for easier build customization
remove QUOTE vestigial token type from token.h
minor fixes from updated new list of builtins and additions