$OpenBSD$
--- build/platform_specific.mk.orig	Fri Apr 25 19:16:11 2008
+++ build/platform_specific.mk	Tue Nov  4 13:00:17 2008
@@ -29,13 +29,19 @@ ifeq ($(TARGET_OS),linux-gnu)
 #	-Wunsafe-loop-optimizations
 endif
 
-# FreeBSD like
+# FreeBSD
 ifeq ($(TARGET_OS),freebsd)
 	CFLAGS+=-D_BSD_SOURCE -D_XOPEN_SOURCE
 endif
 
+# NetBSD
 ifeq ($(TARGET_OS),netbsd)
 	CFLAGS+=-D_BSD_SOURCE -D_NETBSD_SOURCE
+endif
+
+# OpenBSD
+ifeq ($(TARGET_OS),OpenBSD)
+	CFLAGS+=-D_BSD_SOURCE
 endif
 
 # Darwin