Hi Dave,
libthread can be built with and without aolserver/naviserver support. With this support, some cmd names are called differently and the library can be called / initialized as a aolserver/naviserver module. The exactly same happens in AolServer and NaviServer.
Guess you picked a version without that support. When you build a new version, i would recommend to use tclibthread 2.7.0, which has a few memory leaks less. I guess it is the easiest to use the install-script from [1].
all the best
-gustaf neumann
[1] https://openacs.org/xowiki/naviserver-openacs
