$OpenBSD: patch-Makefile,v 1.5 2021/06/15 06:54:44 landry Exp $

Index: Makefile
--- Makefile.orig
+++ Makefile
@@ -199,6 +199,7 @@ endif
 endif
 
 LIBS      += -lrem -lm
+LIBS      += -pthread
 #LIBS      += -L$(SYSROOT)/lib
 
 ifeq ($(OS),win32)
