It appears to be impossible to build an atmel-samd target with either CIRCUITPY_PULSEIO = 0 or CIRCUITPY_ROTARYIO = 0 due to hard-coded references to functions in samd-peripherals/samd/external_interrupts.c (causing link errors).

To replicate, add CIRCUITPY_PULSEIO = 0 or CIRCUITPY_ROTARYIO = 0 to ports/atmel-samd/boards/trinket_m0, then try to build for trinket_m0.

I was able to build using the following modification to external_interrupt_handler to elide references to the relevant functions.

void external_interrupt_handler(uint8_t channel) {
    uint8_t handler = channel_handler[channel];
    if (handler == EIC_HANDLER_PULSEIN) {
#if CIRCUITPY_PULSEIO
        pulsein_interrupt_handler(channel);
#endif
    } else if (handler == EIC_HANDLER_INCREMENTAL_ENCODER) {
#if CIRCUITPY_ROTARYIO
        incrementalencoder_interrupt_handler(channel);
#endif
    }
    EIC->INTFLAG.reg = (1 << channel) << EIC_INTFLAG_EXTINT_Pos;
}

Using this modification, I found the following space savings (for a trinket_m0-based target):

• CIRCUITPY_PULSEIO = 0: 6200 bytes
• CIRCUITPY_ROTARYIO = 0: 208 bytes

Note: I do not recommend this modification as-is. There is almost certainly a better way to handle this, such as building trivial placeholders for these functions when the components are disabled (or using weak symbols). Ideally, samd-peripherals should be further decoupled from the common-hal directory in CircuitPython (or merged back into CircuitPython).