I'm confused about how GCC with the Studio IDE handles include file directories. The IDE provides a means to input via a window form, a list of include file directories. If I do NOT use that, and use "../" type path-relative notations in the .c files, I get file not found errors. It's as if the search is relative to some non-obvious directory, maybe the target directory for the elf.
If I DO list some/all of the directories using the IDE window, things are a mess, unless I put full absolute path names starting with the drive letter. And then the IDE automatically edits this list, later.