I was able to hack and compile the FPC tcl unit and demo using the fpc compiler. I used a separate install of tcl8.0.p2. I'll try tcl8.0.5 and others over time.
This is what the FPC unit does; TCL is a C library of functions that are used to compile TCL shell commands. New TCL shell commands can be created that suit specific purposes. An example might be a new device driver. This FPC unit allows you to program the new TCL shell command in Pascal instead of C. Basically, anything Pascal can do can be "managed" in a powerful shell environment.
I'll do my best to clean up the hacks. Most were related to FPC linking and Windows portability. I just cut out the Windows stuff anyway. The GPC version might link better.
This is probably a better way to I/O to Pascal than discussed earlier. Anyway, it seems to work.