[plt-scheme] Modules and C extensions

PLTers-

When writing a module in C  using the MzScheme API, how do I do things 
like "require" of other modules?

I'm trying to speed up some isolated code by putting into its own 
module and then porting it to C, but the code references variables 
provided by other modules, so I need to make the Namespace 
(Scheme_Env*) that is passed to my C implementation have the "right 
stuff" in it...

The Namespaces and Modules chapter of "Inside MzScheme" explains how to 
export variables from your module, but I can't see how to import other 
modules...

Thanks,
-Felix

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"at this point, i'm ready to
  join the javadoc dev team"  -josh