diff --git a/libs/zita-convolver/zita-convolver/zita-convolver.h b/libs/zita-convolver/zita-convolver/zita-convolver.h
index d804e31139..0448aa491e 100644
--- a/libs/zita-convolver/zita-convolver/zita-convolver.h
+++ b/libs/zita-convolver/zita-convolver/zita-convolver.h
@@ -34,7 +34,7 @@ namespace ArdourZita {
 #endif
 
 /* note: mingw and msvc actually use PTW32's implementation of semaphores */
-#if defined(__linux__) || defined(__GNU__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(PTW32_VERSION) || defined (__WINPTHREADS_VERSION)
+#if defined(__linux__) || defined(__GNU__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__NetBSD__) || defined(PTW32_VERSION) || defined (__WINPTHREADS_VERSION)
 
 #include <semaphore.h>