BeOS tweaks:

BeOS tweaks:
- fseeko and ftello can be found by Configure but
  we do not seem to have prototypes for them so
  let's make up some
- BeOS didn't use to have real sockets (sockets as
  filedescriptors) but the BONE package is supposed
  to fix this.  I do not know how to detect BONEness,
  see hints/beos.sh for a spot that needs to fixed.
- BeOS has O_TEXT != O_BINARY but has no setmode()

p4raw-id: //depot/perl@12756