the only change this results in in the example binaries is in the hackrf-jellybean/systick example, where the the check in systick_set_clocksource for overflowing from the stm32 area gets used.
ARM Interrupt API (see nvic.h). ARM SysTick API (see systick.h). Example using both Interrupt and SysTick and blink LED1/2/3 see systickdemo.c.