I'm trying to install OSW, which needs TCL/TK compiled with multi-threaded support. It doesn't have this in the default Slackware-package, so I decided to recompile it (not much of a choice there ;-) ). So I downloaded the tcl- and tk-packages from the /src, and edited the build-scripts, and then executed the build-scripts. Everything gets installed alright (as far as I can tell) but I don't see the packages showing up in /var/log/packages.

Basically what I want is a real Slackware-package just like the ones on the cd, so I can install/uninstall them with pkgtool. How do I do that?

You use checkinstall

Like Chinaman says, checkinstall is your friend. It's in the /extra directory of the second slackware CD. Install that, then, instead of installing a program from source with make install, type checkinstall instead. Then follow the simple prompts. It will automatically create a Slackware package of whatever you're installing, and then install it, leaving the package in the directory with the source.

Build scripts of Slack usually provide a package in your /tmp dir. But there are some build scripts which don´t provide a package. Checkinstall is a good and easy way of creating packages.