Thanks guys
I figured it out - or I think I did:
The problem was that I am using Fpcupdeluxe, where 'fp' is in 'fpcupdeluxe/fpc/bin/$fpctarget'
I also had a global 'fp' which I have uninstalled now.
I noticed that when I ran 'fp' from it's directory, it worked, after entering the correct include/lib directories.
So, I created a desktop entry for it, so that working directory is set to same.
And it works
This is what I entered into the "Directories" config screen:
Units:
/home/jacmoe/fpcupdeluxe/fpc/units/$fpctarget
/home/jacmoe/fpcupdeluxe/fpc/units/$fpctarget/*
/home/jacmoe/fpcupdeluxe/fpc/units/$fpctarget/rtl
Include files:
/usr/lib/gcc/x86_64-linux-gnu/6
/home/jacmoe/fpcupdeluxe/fpc/lib/$FPCTARGET
Libraries:
/usr/lib/$FPCTARGET
/usr/lib/$FPCTARGET-gnu
/lib/$FPCTARGET
/lib/$FPCTARGET-gnu
/usr/lib/gcc/x86_64-linux-gnu/6.3.0
Edit: If not all of these are necessary, I will probably experiment with removing them, until I get errors.
I am wondering:
Could I have done this differently ?
Right now, I am letting fp have a fp.cfg in it's bin directory.
Thanks for the pointers, Marcov.
And thanks for the encouragement, Leledumbo.