$OpenBSD$

Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -136,7 +136,7 @@ else()
         src/App_unix.cpp
         )
 
-    if (CMAKE_SYSTEM_NAME STREQUAL FreeBSD)
+    if (CMAKE_SYSTEM_NAME STREQUAL OpenBSD)
         set(EXTRA_LIBS pthread)
     else()
         set(EXTRA_LIBS pthread rt dl)