* miscellaneous cleanup:
* cleanup some #ifdefs which were slightly hacky when RP2350 was added; use HAS_ flags in preference to PICO_RP2040/RP2350
* make some dependencies more explicit - i.e. compile if the user doesn't want to include certain libraries
* cleanup some directory A -> directory B relative path names in CMakeLists.txt to be SDK root -> directory B
If you set the timezone, aon_timer_get_time can wrongly apply a
daylight saving time adjustment based on the stack contents. This can
make it appear that time has gone backwards.
Make sure datetime_to_tm initialises tm_isdst to -1.
Fixes#2374
If you call rtc_get_datetime immediately after rtc_set_datetime you get
junk back. According to the datasheet "Writing to the RTC will take
2 clk_rtc clock periods to arrive". So add a delay after calling
rtc_set_datetime in aon_timer_set_time_calendar.
Fixes#2148
* ta_set_timeout can fail to set an alarm
If alarm_pool_irq_handler takes <1us between handling an alarm and
calling ta_set_timeout then no alarms will be set as it will appear as
if an earlier alarm is already armedi before the target time.
Make sure ta_set_timeout always leaves with an alarm set by checking the
armed status.
Fixes#2118
* ta_disable_irq_handler should unarm its timer
