(scm_block_gc, scm_gc_heap_lock): Removed. Removed all uses.
(scm_gc_running_p): Now a macro that refers to the scm_i_thread
field.
(scm_i_sweep_mutex): Now a non-recursive mutex. GC can not happen
recursively.
(scm_igc, scm_i_gc): Renamed former to latter. Changed all uses.
Do not lock scm_i_sweep_mutex, which is now non-recursive, or set
scm_gc_running_p. Do not run the scm_after_gc_c_hook.
(scm_gc): Lock scm_i_sweep_mutex, set scm_gc_running_p and run the
scm_after_gc_c_hook here.
(scm_gc_for_new_cell): Set scm_gc_running_p here and run the
scm_after_gc_c_hook when a full GC has in fact been performed.
(scm_i_expensive_validation_check): Call scm_gc, not scm_i_gc.
* gc-segment.c (scm_i_get_new_heap_segment): Do not check
scm_gc_heap_lock.
* gc-malloc.c (scm_realloc, increase_mtrigger): Set
scm_gc_running_p while the scm_i_sweep_mutex is locked.
Collapsed ensure_state_size and ensure_all_state_sizes into one
function named resize_all_states. Allocate new vectors outside of
single threaded region. Do only simple things inside that region.
(scm_make_fluid, scm_make_dynamic_state): Lock fluid_admin_mutex while
adding to the global lists.
(scm_i_thread): Removed unused signal_asyncs field.
(threads_mark): Do not mark it.
(guilify_self_1): Do not initialize it. Do initialize
continuation_root field.
(do_thread_exit): Do not remove thread from all_threads list.
(on_thread_exit): Do it here, after leaving guile mode.
(sleep_level): Removed.
(scm_i_thread_put_to_sleep): Leave thread_admin_mutex locked when
returning. Do not support recursive sleeps.
(scm_i_thread_wake_up): Expect thread_admin_mutex to be locked on
entry. Do not support recursive sleeps.
AC_CHECK_LIB instead. Do not subst LTDLINCL and LIBLTDL. Do not
add "-DLIBLTDL_DLL_IMPORT" on MINGW32.
* Makefile.am (SUBDIRS): Removed libltdl.
* README: Talk about required external packages.
* autogen.sh: Do not call libtoolize.
