Espruino on ESP8266

it would be good for Gordon to state which value of -std is intended and which version of gcc needs to be used

gnu89 I think? The one that doesn't allow for (int i=0;...). I'd actually quite like to change that though as without it, code is needlessly complicated.

Kolban points out that it's important to get SPI, I2C and similar other things to work

SPI is less of a big deal because Espruino can do software SPI out of the box. It can't do software I2C (yet?) or Serial though.

Also, a big one (IMO) is the utility timer. I don't even know if it's possible (it should be called from a hardware timer via an IRQ), but adding support for that would enable a lot of extra stuff - controlling servos, software PWM, all sorts.