socket-merge-flags should merge shutdown flags.

[Takashi Kato]

It is not specified but can be convenient.

Originally from the below email:

Why do these not print the same thing?

      (write (shutdown-method read write))
      (newline)
1

      (write (socket-merge-flags (shutdown-method read)
                                 (shutdown-method write)))
      (newline)
#t 

[Takashi Kato]

It's like this already...

[Takashi Kato]

This is basically impossible (too hard but too less profit) to do it.

The SHUT_RDWR is not the result of ior but mere enum. (SHUT_RD:0, SHUT_WR:1 and SHUT_RDWR: 2) On Sagittarius implementation of socket-merge-flags is mere bitwise-ior so that we don't have to do a lot of things such as introducing a flag object.

So this won't be fixed.