* __scm.h, alist.h, arbiters.h, async.h, backtrace.h, boolean.h,

* __scm.h, alist.h, arbiters.h, async.h, backtrace.h, boolean.h,
chars.h, continuations.h, coop-defs.h, coop-threads.h,
debug-malloc.h, debug.h, deprecation.h, dynl.h, dynwind.h,
environments.h, eq.h, error.h, eval.h, evalext.h, extensions.h,
feature.h, filesys.h, fluids.h, fports.h, gc.h, gdb_interface.h,
gdbint.h, gh.h, goops.h, gsubr.h, guardians.h, hash.h, hashtab.h,
hooks.h, init.h, ioext.h, iselect.h, keywords.h, lang.h, list.h,
load.h, macros.h, mallocs.h, modules.h, net_db.h, numbers.h,
objects.h, objprop.h, options.h, pairs.h, ports.h, posix.h, print.h,
procprop.h, procs.h, properties.h, ramap.h, random.h, rdelim.h,
read.h, regex-posix.h, root.h, rw.h, scmsigs.h, script.h, simpos.h,
smob.h, socket.h, sort.h, srcprop.h, stackchk.h, stacks.h, stime.h,
strings.h, strop.h, strorder.h, strports.h, struct.h, symbols.h,
tags.h, threads.h, throw.h, unif.h, values.h, variable.h, vectors.h,
vports.h, weaks.h:
Prefixed each each exported symbol with SCM_API.

* continuations.c: Added comment about the use of the extern
declarations of {get,set}context() functions used in the ia64 port.

* continuations.h, gc.c: `__libc_ia64_register_backing_store_base'
is meant to be a `unsigned long *'.