19055: shell/gnrc_icmpv6_echo: acquire ZTIMER_USEC clock for time measurement r=benpicco a=jue89
19188: cpu/gd32v: add periph_adc support r=benpicco a=gschorcht
### Contribution description
This PR provides the `periph_adc` support and is one of a bunch of follow up PRs that complete the peripheral drivers for GD32VF103.
This PR depends on PR #19170 and includes this PR to be compilable since includes the ADC configuration also for Sipeed Longan Nano board.
### Testing procedure
`tests/periph_adc` should work on any GD32VF103 board.
### Issues/PRs references
Depends on PR #19170
19225: sys/net/dhcpv6: include IA Prefix Option in SOLICIT r=benpicco a=benpicco
Co-authored-by: Jue <me@jue.yt>
Co-authored-by: Gunar Schorcht <gunar@schorcht.net>
Co-authored-by: Benjamin Valentin <benjamin.valentin@ml-pa.com>
Previously `shell_commands` was a "catch-all" module that included
shell commands for each and every used module that has a shell
companion. Instead, the new `shell_cmds` module is now used to provide
shell commands as individually selectable submodules, e.g.
`cmd_gnrc_icmpv6_echo` now provides the ICMPv6 echo command (a.k.a.
ping).
To still have a "catch all" module to pull in shell commands of modules
already used, `shell_cmds_default` was introduced. `shell_commands`
depends now on `shell_cmds_default` for backward compatibility, but
has been deprecated. New apps should use `shell_cmds_default`
instead.
For a handful of shell commands individual selection was already
possible. Those modules now depend on the corresponding `cmd_%` module
and they have been deprecated.
