playing with LP, using noweb. I put related header, source and
test files into a single .nw file. But that means that if I make a change
in the source component, the header file is re-extracted, with the result
that many files which haven't actually changed are recompiled.
Any suggestions on simplifying the process?

<p><blockquote><b>A.</b> 
<pre>
notangle -Rheader foo.nw | cpif foo.h
</pre>
To understand why this works, see the <tt>cpif</tt> man page.
</blockquote><p>

<b>Q.</b>  What are these weird Make