Components should set the COMPONENT_REQUIRES & COMPONENT_PRIVATE_REQUIRES variables to define their
requirements.
* Original commit: espressif/esp-idf@1cb5712463
* Philosophical: "explicit is better than implicit".
* Practical: Allows useful errors if invalid directories given in components as the defaults aren't
always used. Also trims the -I path from a number of components that have no actual include
directory.
* Simplifies knowing which components will be header-only and which won't
* Original commit: espressif/esp-idf@4f1a856dbf
