46dbd867f2
`tests/periph` calls the functions `rtc_get_alarm` and `rtc_set_alarm` from an ISR. Depending on the implementation of `periph_rtc`, however, these functions use `newlib` functions such as `localtime` and `mktime`, which in turn call the `newlib` lock function `__tz_lock`. This can lead to a system lock if the `newlib` with real lock functionality is used instead of the `newlib_nano`.
Expected result
When everything works as expected, after start-up, 4 alarm messages are displayed every 2 seconds.
Background
Test for the low-level RTC driver.