autoconfigure FILE array using getdtablesize()

autoconfigure FILE array using getdtablesize()
changed all struct _iobuf to FILE
many miscellaneous changes

SCCS-vsn: lib/libc/stdio/clrerr.c 4.2
SCCS-vsn: lib/libc/stdio/fdopen.c 4.5
SCCS-vsn: lib/libc/stdio/fgets.c 4.2
SCCS-vsn: lib/libc/stdio/fopen.c 4.4
SCCS-vsn: lib/libc/stdio/fprintf.c 4.4
SCCS-vsn: lib/libc/stdio/fputc.c 4.2
SCCS-vsn: lib/libc/stdio/fputs.c 4.3
SCCS-vsn: lib/libc/stdio/freopen.c 4.3
SCCS-vsn: lib/libc/stdio/fseek.c 4.4
SCCS-vsn: lib/libc/stdio/ftell.c 4.3
SCCS-vsn: lib/libc/stdio/wbuf.c 4.9
SCCS-vsn: lib/libc/stdio/filbuf.c 4.10
SCCS-vsn: lib/libc/stdio/ungetc.c 4.3
SCCS-vsn: lib/libc/stdio/rewind.c 4.3
SCCS-vsn: lib/libc/stdio/gets.c 4.2
SCCS-vsn: lib/libc/stdio/setbuf.c 4.3
SCCS-vsn: lib/libc/stdio/sprintf.c 4.2
SCCS-vsn: lib/libcompat/4.3/strout.c 4.2
SCCS-vsn: lib/libc/stdio/setbuffer.c 4.5
SCCS-vsn: lib/libc/stdio/vfscanf.c 4.3
SCCS-vsn: lib/libc/stdio/findfp.c 1.2
SCCS-vsn: lib/libc/stdio/fdopen.c 4.5