Fix `clock` CPU utilization

[MattCatz]

No need to redraw if there has not been any events. Poll for events about every 100 ms. Drops utilization from around 25% to less than 0.

Also swap -ffunction-sections -fdata-sections for LTO to save ~5 Kb of memory when loaded and probably an immeasurable amount of performance.

Below is the size difference using LTO:

Addresses part of issue: https://github.com/OnionUI/Onion/issues/107