…onal

sys: make uart_stdio RX optional (attempt #2)

The evtimer_msg test is expanded to also delete entries.

Furthermore the messages that are printed should now show
numbers that are very close (if not equal). Something like
this:
At    740 ms received msg 0: "#2 supposed to be 740"
At   1081 ms received msg 1: "#0 supposed to be 1081"
At   1581 ms received msg 2: "#1 supposed to be 1581"
At   4035 ms received msg 3: "#3 supposed to be 4035"

The function evtimer_print is also called to show the
intermediate status of evtimer entries.

The test randomly fails on `native` due to timers being not accurate but
it cannot be otherwise. So better disable it than raising fake errors.

    main(): This is RIOT! (Version: buildtest)
    Testing generic evtimer
    This should list 2 items
    ev #1 offset=1000
    ev #2 offset=500
    This should list 4 items
    ev #1 offset=659
    ev #2 offset=341
    ev #3 offset=500
    ev #4 offset=2454
    Are the reception times of all 4 msgs close to the supposed values?
    At    662 ms received msg 0: "#2 supposed to be 659"
    At   1009 ms received msg 1: "#0 supposed to be 1000"
    At   1511 ms received msg 2: "#1 supposed to be 1500"

    Traceback (most recent call last):
      File "/tmp/dwq.0.3125418833043728/ef3af88c4b3615788b164464a437df5c/tests/evtimer_msg/tests/01-run.py", line 33, in <module>
        sys.exit(run(testfunc))
      File "/tmp/dwq.0.3125418833043728/ef3af88c4b3615788b164464a437df5c/dist/pythonlibs/testrunner/__init__.py", line 29, in run
        testfunc(child)
      File "/tmp/dwq.0.3125418833043728/ef3af88c4b3615788b164464a437df5c/tests/evtimer_msg/tests/01-run.py", line 26, in testfunc
        assert(actual in range(expected - ACCEPTED_ERROR, expected + ACCEPTED_ERROR))
    AssertionError

The ENTROPY test always fails on this board

main(): This is RIOT! (Version: buildtest)
mbedtls test

  SHA-224 test #1: passed
  SHA-224 test #2: passed
  SHA-224 test #3: passed
  SHA-256 test #1: passed
  SHA-256 test #2: passed
  SHA-256 test #3: passed

  ENTROPY test: failed

19270: drivers/at24cxxx: implement _mtd_at24cxxx_read_page r=benpicco a=HendrikVE

### Contribution description

The function `read_page` was missing which lead to (from a user perspective) undefined behavior on the MTD layer.

### Testing procedure

Any application using MTD in conjunction with a board with an at24cxxx.


19271: core/xfa: disable asan on llvm r=benpicco a=Teufelchen1

### Contribution description
Hi! 🦎

When using llvm and address sanitation, the XFA trip the sanitizer.
This PR attempts to fix this by adding the `no_sanitize` attribute to the XFA macros. Sadly, this attribute is not known by gnu, a guard is hence needed. I'm open for alternatives as I dislike this solution but it is the best I could come up with.

### Testing procedure

Before this patch:

Go to `examples/gnrc_minimal` and run `TOOLCHAIN=llvm make all-asan` and then `make term`.
You should see an error similar to this:
```
==3374719==ERROR: AddressSanitizer: global-buffer-overflow on address 0x080774e0 at pc 0x0804af5e bp 0x0808eb88 sp 0x0808eb78
READ of size 4 at 0x080774e0 thread T0
    #0 0x804af5d in _auto_init_module /RIOT/sys/auto_init/auto_init.c:40
    #1 0x804af5d in auto_init /RIOT/sys/auto_init/auto_init.c:339
    #2 0x804b375 in main_trampoline /RIOT/core/lib/init.c:56
    #3 0xf76bc7b8 in makecontext (/lib32/libc.so.6+0x4a7b8)
...
``` 
After applying this PR, the example can be build and run with llvm or gcc, with or without asan.



Co-authored-by: Hendrik van Essen <[email protected]>
Co-authored-by: Teufelchen1 <[email protected]>

18392: drivers/servo: reimplement with high level interface r=benpicco a=maribu

### Contribution description

The previous servo driver didn't provide any benefit over using PWM directly, as users controlled the servo in terms of PWM duty cycles. This changes the interface to provide a high level interface that abstracts the gory PWM details.

In addition, a SAUL layer and auto-initialization is provided.

### Testing procedure

The test application provides access to the servo driver via the `saul` shell command.

```
> saul
2022-08-02 22:12:31,826 # saul
2022-08-02 22:12:31,827 # ID	Class		Name
2022-08-02 22:12:31,830 # #0	ACT_SWITCH	LD1(green)
2022-08-02 22:12:31,832 # #1	ACT_SWITCH	LD2(blue)
2022-08-02 22:12:31,834 # #2	ACT_SWITCH	LD3(red)
2022-08-02 22:12:31,837 # #3	SENSE_BTN	B1(User button)
2022-08-02 22:12:31,838 # #4	ACT_SERVO	servo
> saul write 4 0
2022-08-02 22:12:41,443 # saul write 4 0
2022-08-02 22:12:41,445 # Writing to device #4 - servo
2022-08-02 22:12:41,447 # Data:	             0 
2022-08-02 22:12:41,450 # [servo] setting 0 to 2949 (0 / 255)
2022-08-02 22:12:41,453 # data successfully written to device #4
> saul write 4 256
2022-08-02 22:12:45,343 # saul write 4 256
2022-08-02 22:12:45,346 # Writing to device #4 - servo
2022-08-02 22:12:45,347 # Data:	           256 
2022-08-02 22:12:45,351 # [servo] setting 0 to 6865 (255 / 255)
2022-08-02 22:12:45,354 # data successfully written to device #4
```

Each write resulted in the MG90S servo that I connected to move to the corresponding position.

### Issues/PRs references

Co-authored-by: Marian Buschsieweke <[email protected]>