Remove all \bcode / \ecode cruft; this is no longer needed.  See previous
checkin of myformat.sty.

Change "\renewcommand{\indexsubitem}{(...)}" to "\setindexsubitem{(...)}"
everywhere.

Some other minor nits that I happened to come across.
diff --git a/Doc/libcmath.tex b/Doc/libcmath.tex
index c9886bb..147fa6e 100644
--- a/Doc/libcmath.tex
+++ b/Doc/libcmath.tex
@@ -2,7 +2,7 @@
 \label{module-cmath}
 
 \bimodindex{cmath}
-\renewcommand{\indexsubitem}{(in module cmath)}
+\setindexsubitem{(in module cmath)}
 This module is always available.
 It provides access to mathematical functions for complex numbers.
 The functions are: