detect OpenBSD

Index: src/gui/remoteAudio.nim
--- src/gui/remoteAudio.nim.orig
+++ src/gui/remoteAudio.nim
@@ -4,7 +4,7 @@ import discord_rpc
 import ../utils, ../api
 import audio, configuration
 
-when defined(linux):
+when defined(linux) or defined(openbsd):
   import math
   import ../utils
   import qt, audio, configuration
