sim-ThornGuide target merges all TeX documentation files and produces a single PDF file as output. This break is
documentation.tex file use
\newcommand to define (possibly conflicting commands). Pull request https://bitbucket.org/cactuscode/cactus/pull-requests/83/cactus-support-newcommand-in-documentation/diff encloses the extracted part in a
\endgroup thus ensuring that commands are only locally defined for each thorn.