patch applied (packages/unix): Clarify behavior of "awaitSignal Nothing", export SignalSet that includes all signals reserved by RTS (#4504)

[Simon Marlow]

Wed Dec  8 10:38:49 PST 2010  Dmitry Astapov <dastapov at gmail.com>
  * Clarify behavior of "awaitSignal Nothing", export SignalSet that includes all signals reserved by RTS (#4504)

    M ./System/Posix/Signals.hsc -4 +17

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=packages/unix;a=darcs_commitdiff;h=20101208183849-5701e-da76b245f1e22805f7901ec82e6a219cebe56cf6.gz