* gc-malloc.c (scm_calloc): try to use calloc() before calling
scm_realloc().
* gc-segment.c (scm_i_initialize_heap_segment_data): remove card
init loop; handle this from scm_init_card_freelist()
* gc-card.c (scm_init_card_freelist): init bit vector here.
malloc.
* gc-segment.c (scm_i_get_new_heap_segment): remove cluster cruft:
only use SCM_MIN_HEAP_SEG_SIZE.
* ports.c (scm_add_to_port_table): add backwards compatibility
function
* ports.h: use scm_i_ prefix for port table and port table size.
* gc-card.c ("sweep_card"): set scm_gc_running while sweeping.
* gc.c (scm_i_expensive_validation_check): separate expensive
validation checks from cheap ones.
