Not really. The form # include < h-char-sequence > new-line
imports a header, while the form# include " q-char-sequence " new-line
imports a source file, because headers aren't necessarily source files, and might be magic. But that's likely to confuse everyone. And if a "source file" isn't found, it's reprocessed as a header. http://eel.is/c++draft/cpp.include
It shouldn't matter too much for this, but it's worth keeping in mind that `make` doesn't work with paths, it works with targets, and spelling counts, even if they refer to the same path. That is ./path/file.h and ./path/something/../file.h have no relation to each other from make's point of view.