\myheading{CBMC}

\renewcommand{\CURPATH}{puzzles/zebra/CBMC}

CBMC solution is simpler, we don't define, which variables are subject to search.

\lstinputlisting[style=customc]{\CURPATH/CBMC_zebra.c}

\lstinputlisting[style=customc]{\CURPATH/CBMC_zebra.c.log}

The solution is no different, of course.