Pthreads is now required

CMakeLists.txt

@@ -24,8 +24,9 @@ list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
 ### -------------- Pthread ---------------------------
 message("Start check for pthread")
 include(FindThreads)
-find_package(Threads)
+find_package(Threads REQUIRED)
 set_target_properties(Threads::Threads PROPERTIES THREADS_PREFER_PTHREAD_FLAG TRUE)
+list(APPEND cdo_compile_defintions HAVE_LIBPTHREAD=1)
 
 ### -------------- WordExp ---------------------------
 message("Start check for wordexp")