$OpenBSD$

Index: build_files/Modules/CompilerSettings.cmake
--- build_files/Modules/CompilerSettings.cmake.orig
+++ build_files/Modules/CompilerSettings.cmake
@@ -36,7 +36,7 @@ elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wnull-dereference -Wdelete-non-virtual-dtor -Wsign-compare -Wswitch")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wreturn-type -Wself-assign -Wunused-argument -Wunused-function -Wtautological-compare")
     #OpenMP support under Linux with clang
-    if (UNIX)
+    if (!UNIX)
         FIND_PACKAGE(OpenMP REQUIRED)
         SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
         SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
