Two targets, two header files with the same name how to use each header for the right target?
The problem I was having was 2 fold:
You need to remove the header files from the project. If they're in Xcode, in the file manager, then they will automatically be included in the project.
You need to use relative paths to your folders in "User Header Search Paths". I was using
${PROJECT_DIR}/path/to/header/folder
which gave the right path, but didn't seem to work properly. Changing the entry to./path/to/header/folder
instead worked fine.