It was a windows32 application, not console.
"Enable Microsoft extensions" and "Enable Pelles C extensions" didn't make any difference.
Using "file-> new -> project" seems to create some kind of "starter program".
How do I get my my source file in there instead? I can't seem to find anything in
the menus to do that.
Go back into the new project dialog... scroll down... You will see "win32 program" ... not the wizard... start a project there, set the paths etc as you need them... then when POIDE shows you the empty project, exit POIDE, copy your files into the project folder and then relaunch POIDE and right click on the empty project in the treeview... you will see, "Add files to project"... select your files and add them.
You may have to make some changes in the project options pane, but it should work.
The extensions should be enabled... and, depending on your code you may need "Define Compatibility Names" as well.
I'm thinking you're tripping over differences between IDEs and settings... be patient, Pelles C does take a little bit of getting used to.
Also note that Borland has some pretty non-standard stuff in their libraries and compiler... so you may have to do some fixing up on your code to get it to work...