<A NAME="htoc20">3.4.1</A>&#XA0;&#XA0;Defining a default compilation rule</H3><P>Let&#X2019;s start with part 2, defining a generic compilation rule. We&#X2019;ll define the build rule as an
<EM>implicit</EM> rule. To handle the include path, we&#X2019;ll define a variable <CODE>CAT_INCLUDES</CODE> that
specifies the include path. This will be an array of directories. To define the options, we&#X2019;ll use
a lazy variable (Section&#XA0;<A HREF="omake-language-examples.html#section:lazy">7.5</A>). In case t