$OpenBSD: patch-gtk2hs-buildtools_cabal,v 1.2 2013/07/18 22:08:48 kili Exp $
--- gtk2hs-buildtools.cabal.orig	Mon Nov 12 00:26:45 2012
+++ gtk2hs-buildtools.cabal	Tue Jul  9 21:10:55 2013
@@ -109,7 +109,7 @@ Executable gtk2hsC2hs
                         c2hs/base/syms
                         c2hs/base/syntax
         c-sources:      c2hs/toplevel/c2hs_config.c
-        if os(darwin)
+        if os(darwin) || os(openbsd)
           cpp-options:  -D_C2HS_CPP_IS_GCC
         else
           cpp-options:  -D_C2HS_CPP_LANG_SINGLE
