Index: src/common/ref.h
--- src/common/ref.h.orig
+++ src/common/ref.h
@@ -27,7 +27,7 @@ struct ref {
 };
 
 #if (defined(__linux__) || defined(__GLIBC__) || defined(__FreeBSD__) || \
-		defined(__darwin__) || defined(__NetBSD__))
+		defined(__darwin__) || defined(__NetBSD__) || defined(__OpenBSD__))
 
 /*
  * Get a reference by incrementing the refcount.
@@ -58,6 +58,6 @@ static inline void ref_put(struct ref *r,
 
 #else
 #error "OS not supported"
-#endif /* __linux__, __GLIBC__, __FreeBSD__, __darwin__, __NetBSD__ */
+#endif /* __linux__, __GLIBC__, __FreeBSD__, __darwin__, __NetBSD__, __OpenBSD__ */
 
 #endif /* TORSOCKS_REF_H */