Charles,
Do I just install 1.18 and forget about 1.16? Or should I delete all of the 1.16 files first?
You can do either. There should be no conflicts either way. All of the 1.16 files should be overwritten by the 1.18 versions in any case.
I didn't see a Makefile target "uninstall", although there are some "*clean*" options there.
The 'clean' options just tidy up the build tree, but alternatively, it is safe simply to delete the whole build tree after installing. You are right that there is no 'uninstall' option, and perhaps there should be. If you want to delete an older version of nhc98, here are the places that installed files live: prefix=/usr/local (usually) $prefix/bin/ $prefix/lib/nhc98 $prefix/lib/hmake $prefix/include/nhc98 $prefix/man/man1 $prefix/doc/nhc98
Perhaps you could add this topic to your website?
A good idea. Regards, Malcolm