Add dummy_thread[ing] sections and reference these from libthread[ing].
diff --git a/Doc/lib/lib.tex b/Doc/lib/lib.tex
index c7a236a..dc8059a 100644
--- a/Doc/lib/lib.tex
+++ b/Doc/lib/lib.tex
@@ -164,6 +164,8 @@
 \input{libselect}
 \input{libthread}
 \input{libthreading}
+\input{libdummythread}
+\input{libdummythreading}
 \input{libqueue}
 \input{libmmap}
 \input{libanydbm}