Best way to add a line to a config file from another package?

[Vasile Gaburici]

I need to add line to /usr/share/texmf/dvips/config/config.ps to get
some extra functionality enabled for lcdf-typetools, namely Type 42
support. The config.ps file is properly marked as a config file in
texlive-texmf-dvips. Is there some infrastructure that's normally used
to hack config files or should I just echo "..." >> config.ps?