1. move chip-specific code(e.g. encryption) into IDF_TARGET directory 2. splict app-only code to idf directory which won't be compiled into bootloader
bootloader_support: Rename include_priv directory to include_bootloader See merge request idf/esp-idf!2686
Old rationale for "priv" no longer applies. As reported here: https://esp32.com/viewtopic.php?f=13&t=6155&p=27151#p26601