[spin2][NuCode] `pinw()` does nothing (optimization-related)

[avsa242]

Hey Eric,

When the NuCode backend is used, pinw() doesn't seem to function when built with -O1 or higher.

I've narrowed it down to the special function handling opt specifically -Ospecial-functions. When this is disabled, it functions properly.

This snippet blinks one of the LEDs on a non-PSRAM EDGE:

pub {++opt(!special-functions)} main() | p                                                              

    p := 0
    repeat
        pinw(57, p)
        p ^= 1
        waitms(250)

Cheers