I tried following the "Installing with Boards Manager" instructions and installed ESP8266 from there. But again the same result. Missing components, being the fisrt compiling error again the missing "queue.h" (I managed to avoid the initial ESP8266WiFi.h missing error by copying the ESP8266WiFi library in the libraries directory).
So a little bit lost as I am not an expert on environments or programming... Anyway, thanks a lot for your feedback!