DOCBOOK: Repost: Recommended way to include external C source

Bernd Kreimeier writes: 
 > What is the recommended way to handle external C source
 > (i.e. having the parser include the entity, and translate 
 > & into &amp; and <> into &lt;&gt; etc.)?

In other words, is there anything like
  <!ENTITY   sample.c  SYSTEM "sample.c" CDATA plaintxt >
and how do I connect a conversion script with a NOTATION?

Or do I have to fall back on Makefiles and sed/awk 
conversion scripts because the DocBook toolchain (or
SGML as such) is simply not able to handle this?


                                          b.