Update current lvgl 8 to use new libm/c

[thiccaxe]

The current version of lvgl 8.- works in pros before the libc update. For newer versions, an update is required. We are updating this because lvgl 9 (from which branch future development efforts will continue) contains api changes (mostly function renames), so there is still the chance that a developer wants to use the faster libm/c with lvgl 8.

If you want to build this project for yourself please use arm-gnu-toolchain-13.3.rel1-(architecture-of-your-cpu)-arm-none-eabi/ because older releases and "newer releases" (not sure how fedora is on arm-gnu-toolchain 14?) do not work.