Compiling for the ESP8266 on the Raspberry Pi (ARM)

Hi,
I have installed on a Raspberry Pi (Raspbian Buster) the ESP8266 board manager from the library of the Arduino IDE 1.8.13 using the URL:
http://arduino.esp8266.com/stable/package_esp8266com_index.json.

I seems to work so far, but upon compling the compiler complained to miss the libraries FS.h and TZ.h.

Both libraries are part of the core and should have been installed together with the board manager.
Do someoine know, why they are missing and where can I retrofit them?