[Lazarus] Running external process from within Lazarus design package

[Bernd]

I need to run an external program from within my lazarus package.
Unfortunately it will need significant time to run, so I cannot just
wait for it in the main thread and also it will produce some important
diagnostic console output that I would like to print into the messages
window.

Is there any possibility to use the same mechanism that is used when
compiling or when running other external tools (tools menu) from
within my lazarus package? It would be enough if someone could point
me to some existing lines of code where this has been done already or
maybe just name the needed ide units or the T<whatever>Boss or manager
class that is responsible for this and where to find it.

Bernd