* filesys.c (scm_chown): use SCM_FPORT_FDES.

	* filesys.c (scm_chown): use SCM_FPORT_FDES.
	(scm_chmod, scm_stat, scm_truncate_file: likewise.
	* fports.c (scm_fdes_to_port), ports.c (scm_void_port),
	filesys.c (scm_opendir):
	restore defer interrupts while the port is constructed.
*	(scm_setvbuf): if mode is _IOFBF and size is not supplied,
	derive buffer size from fdes or use a default.
	(scm_fdes_to_port): use setvbuf instead of creating the buffers
	directly.
	* filesys.c (scm_fsync): use SCM_FDES.
	* filesys.c (scm_fcntl): get fdes from fport.
	(set_element, get_element): likewise.
	* filesys.c (scm_open): adjust port_mode for O_APPEND and O_CREAT.
	ports.c fports.c ioext.c posix.c socket.c net_db.c filesys.c:
	removed all uses of SCM_DEFER/ALLOW ints for now.  they were mainly
	just protecting errno.  some may need to be put back.
*	* ports.c (scm_drain_input): new procedure.
	ports.h: prototype.
	* fports.c (FPORT_READ_SAFE, FPORT_WRITE_SAFE, FPORT_ALL_OKAY,
	pre_read, pre_write): removed.
	(local_fputc, local_fputs, local_ffwrite): use write, not stdio.
	(scm_standard_stream_to_port): change first arg from FILE * to
	int fdes.
	(local_fflush): flush fdes, not FILE *.
	* fports.h (SCM_NOFTELL): removed.
	* genio.c, ports.c: don't include filesys.h.
	* genio.c (scm_getc): don't use scm_internal_select if FPORT.
	do it in fports.c:local_fgetc.
	* genio.c: don't use SCM_SYSCALL when calling ptob procedures.
	do it where it's needed in the port smobs.
	* filesys.c (scm_input_waiting_p): moved to fports.c, stdio
	  buffer support removed.  take SCM arg, not FILE *.
	* filesys.h: prototype moved too.
	* fports.c (scm_fdes_to_port): new procedure.
	(local_fgetc): use read not fgetc.
	(local_fclose): use close, not fclose.
	(local_fgets): use read, not fgets
	* fports.h: prototype for scm_fdes_to_port.
	* fports.h (scm_fport): new struct.
	* fports.c (scm_open_file): use open, not fopen.
	#include fcntl.h
	* ports.h (struct scm_port_table): change stream from SCM to void *.
	* ports.c (scm_add_to_port_table): check for memory allocation error.
	(scm_prinport): remove MSDOS hair.
	(scm_void_port): set stream to 0 instead of SCM_BOOL_F.
	(scm_close_port): don't throw errors: do it in fports.c.