wta for range errors (ASSERT still needs work).
* error.c, error.h (scm_out_of_range): new procedure.
* error.c, error.h (scm_out_of_range_key): new key.
* posix.c (scm_sync): #else was missing.
* error.c, error.h: append _key to names scm_num_overflow and
scm_system_error.
* __scm.h (SCM_SYSMISSING, SCM_NUM_OVERFLOW): use SCM_BOOL_F instead
of consing an empty list.
(SCM_SYSERROR etc.): move into error.c, make them procedures instead
of macros, saves code and string space.
error.c, fports.c, numbers.c, posix.c, ioext.c, filesys.c, socket.c,
fdsocket.c, simpos.c: change names of SCM_SYSERROR etc., to
lower case. Rename scm_syserror_m to scm_syserror_msg.
error.h: prototypes for new procedures.
* error.c, error.h: setup scm_num_overflow key.
* __scm.h: SCM_NUM_OVERFLOW: macro for reporting numerical overflow.
Remove definition of SCM_OVSCM_FLOW.
* fports.c (scm_open_file): use SCM_SYSERROR_M.
* __scm.h: SCM_SYSERROR_M: new macro for system errors with an
explicit message and args.
* error.c, error.h, __scm.h: change system_error_sym to
scm_system_error.
* error.c (system_error_sym): remove leading %% from the Scheme name
"%%system-error".
* __scm.h (SCM_SYSMISSING): Redefine using lgh_error.
* boot-9.scm: remove leading %% from references to '%%system-error.
(%%handle-system-error): don't pass all the thrown arguments when
aborting, just the key and subr.
Remove the code to "Install default handlers for built-in errors."
Remove the definition of the syserror procedure.
Associate 'numerical-overflow with default handler.
* Makefile.in (c_files): add strerror.c.
* strerror.c: new file from Emacs' sysdep.c.
maybe configure should also check for sys_errlist.
* configure.in (AC_REPLACE_FUNCS): add strerror.
