```
sysctl kern.supported_archs: return correct value
in case COMPAT_FREEBSD32 was enabled in config but hardware does not
support executing 32bit binaries.
```
```
FEATURE compat_freebsd_32bit: report correct value on arm64
depending on hardware support for aarch32.
```
```
Add FEATURE_DYN() macro
to report feature that depends not only static kernel config, but also
might be affected by runtime.
```