Make specs pass on OpenBSD

Skip Process clockres specs that don't work on either FreeBSD or
Solaris/AIX in addition to OpenBSD.

Run most current String#crypt specs on non-OpenBSD, and add a new
set of crypt specs for OpenBSD, which support bcrypt but not DES
in crypt(3).

Use @server.connect_address instead of @server.getsockname in some
socket tests, as OpenBSD does not treat connection to all zero
IPv4 or IPv6 addresses as connection to localhost.

When trying to connect using UDP on an unsupported address family,
allow Errno::EPROTONOSUPPORT in addition to Errno::EAFNOSUPPORT,
as OpenBSD raises the former.

spec/ruby/library/socket/udpsocket/initialize_spec.rb

@@ -30,7 +30,13 @@ describe 'UDPSocket#initialize' do
     @socket.binmode?.should be_true
   end
 
-  it 'raises Errno::EAFNOSUPPORT when given an invalid address family' do
-    lambda { UDPSocket.new(666) }.should raise_error(Errno::EAFNOSUPPORT)
+  it 'raises Errno::EAFNOSUPPORT or Errno::EPROTONOSUPPORT when given an invalid address family' do
+    begin
+      UDPSocket.new(666)
+    rescue Errno::EAFNOSUPPORT, Errno::EPROTONOSUPPORT => e
+      [Errno::EAFNOSUPPORT, Errno::EPROTONOSUPPORT].should include(e.class)
+    else
+      raise "expected Errno::EAFNOSUPPORT or Errno::EPROTONOSUPPORT exception raised"
+    end
   end
 end