Use shorter labels; using long labels creates problems on the Macintosh.

(Thanks, Just!)
diff --git a/Doc/lib/libcgi.tex b/Doc/lib/libcgi.tex
index 4b01862..cb0a6fb 100644
--- a/Doc/lib/libcgi.tex
+++ b/Doc/lib/libcgi.tex
@@ -15,7 +15,7 @@
 written in Python.
 
 \subsection{Introduction}
-\nodename{Introduction to the CGI module}
+\nodename{cgi-intro}
 
 A CGI script is invoked by an HTTP server, usually to process user
 input submitted through an HTML \code{<FORM>} or \code{<ISINPUT>} element.
diff --git a/Doc/lib/libxdrlib.tex b/Doc/lib/libxdrlib.tex
index 6157c9d..56459f8 100644
--- a/Doc/lib/libxdrlib.tex
+++ b/Doc/lib/libxdrlib.tex
@@ -206,7 +206,7 @@
 
 
 \subsection{Exceptions}
-\nodename{Exceptions in xdrlib module}
+\nodename{xdr-exceptions}
 
 Exceptions in this module are coded as class instances: