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/lib/libos.tex b/Doc/lib/libos.tex
index 763d2f3..58f268c 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -26,7 +26,7 @@
 In addition to whatever the correct OS dependent module exports, the
 following variables and functions are always exported by \code{os}:
 
-\renewcommand{\indexsubitem}{(in module os)}
+\setindexsubitem{(in module os)}
 
 \begin{datadesc}{name}
 The name of the OS dependent module imported.  The following names