Strange-ness with SIGINFO and SIGWINCH about unix

[erikd]

Furthermore, why is the handling of these two signals so very different from the more commonly used ones in System.Posix.Signals.hs.

I suspect that since these were never used (because of the configure.ac issue) they bit rotted, and should be brought into line with the rest.

[erikd]

A couple of options here:

• Drop these (ie the file System/Posix/Signals/Exts.hsc) completely. This file was added in 2004 and I can see no evidence of it working correctly after this commit:

  commit 1c4608e
  Author: Simon Marlow [email protected]
  Date: Thu Feb 19 10:05:32 2009 +0000

• Keep them, but make them work like all the other signals and drop infoEvent and windowChange as they add nothing and have not been available since 2009.

• Move the definitions of sigINFO and sigWINCH from System/Posix/Signals/Exts.hsc to System/Posix/Signals.hsc and make them work like all the other signals. They aren't POSX, but does that matter? They can be documented as being "non-POSIX" and where they are not available, they will have a value of -1, the same as any other signal that is not available.

I kind of like the last option.