boards: make BOARD=native an alias for BOARD=native32

[mguetschow]

Contribution description

(still WIP, using CI for testing)

TODO

• make native an alias for native32 or native64 depending on the host architecture (see boards: rename native64 -> native #21100 (comment))
• somehow (re-)add documentation for BOARD=native
• add build system test for alias
• think about implications of using native (or any alias, for that matter) in BOARD_WHITELIST et al.

Testing procedure

make BOARD=native and make BOARD=native32 should produce the same output for now

Issues/PRs references

Alternative to #21100

[riot-ci]

Murdock results

✔️ PASSED

c0f3555 boards/doc.txt: document native board alias for native32

Success	Failures	Total	Runtime
148411	0	148411	01h:39m:11s

Artifacts

• Documentation preview

[mguetschow]

Hum, somehow this PR wrongly changes the output of make info-boards-supported causing a bunch of "missing periph" build failures.

Evidence: make -C tests/core/thread_float info-boards-supported | grep gba_cartridge returns nothing on master, but does so with this PR.

I can't tell why though.

[mguetschow]

I can't tell why though.

I can now. It's because I need to use override in board_alias.inc.mk to be able to alter the BOARD variable if passed from the command line. override can only be overwritten by another override, so adding that in info-global.inc.mk.

Should work now. Not sure if this is the right fix though.