eCxx
A C++ library for AVR and NodeMCU
...On one side, eCxx supports the original megaAVR series (ATmega328P, ATmega1284P, ATmega2560, ATmega32U4, AT90USB1286, etc.) as well as the new megaAVR 0-Series (ATmega4808, ATmega4809, etc.).
On the other side, while eCxx is primarily designed to work in NodeMCU, it should also support other ESP-12 based design as well as ESP-01 based design.
The Makefile build system and some of the tools would only run on Linux.