diff --git a/cf/pthreads.m4 b/cf/pthreads.m4
index 592494c87..d89adbdbc 100644
--- a/cf/pthreads.m4
+++ b/cf/pthreads.m4
@@ -44,6 +44,7 @@ case "$host" in
 	;;
 mips-sgi-irix6.[[5-9]])  # maybe works for earlier versions too
 	enable_pthread_support=yes
+	PTHREADS_LIBS="-lpthread"
 	;;
 *)
 	enable_pthread_support=no