Fix: Python2 Paths for Legacy Kernel v5.10 with Edge Release

[Torndeco]

I encountered some python path issues when using legacy kernel with edge release.
Rock5b Legacy Kernel v5.10 & Ubuntu Lunar.

Debian Bullseye (not tested) & Ubuntu Lunar
Don't have a /usr/bin/python symlink that points to python2, due to deprecation of Python 2 (https://wiki.debian.org/Python)
This breaks some old python scripts etc in linux-headers deb

There is also a python-is-python3 that creates a /usr/bin/python symlink pointing to python3
So better to patch the legacy kernel incase cause issues later on.

The patchfile is based off radxa kernel linux-5.10-gen-rkr3.4

Note: Any legacy kernel build (version 5.10 and previous) will be effected on a edge release.

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Sorry if not implemented in correct place or patchfile name, first time using armbian build system & bash scripting etc
Thanks

[rpardini]

This is handled differently in armbian-next. We inject a PATH entry containing Armbian-managed python symlink pointing to python2 if available. That way any u-boot / kernel work without requiring patches.
The removal of python2 from sid / bookworm / lunar is a separate problem, though. Some stuff might work with a fake python3 link, some won't (specially u-boot).

@Torndeco can you test armbian-next branch, without this patch?

[Torndeco]

I haven't had time to look at changes to armbian-next
I assume its a rewrite of the build system and possible configs to make more manageable

Are you talking about managing the python symlink in the build system or target os / image.
If the latter do you have a link to were this implemented? (I don't mind getting another sdcard to use for testing if so)

i.e
I can build packages fine, running the build system on a stable branch.
This pull request is to fix installing legacy linux-headers deb package on a Rock5b running Lunar.
As that is broken due to python paths due to deb postinst running make etc

[rpardini]

python paths due to deb postinst running make etc

Ahn ok I had missed that. Indeed I'll have to handle this: postinst will also need to inject a PATH/symlink before running make. Its not gonna be practical to patch 30+ kernels for this...

[igorpecovnik]

This pull request is to fix installing legacy linux-headers deb package on a Rock5b running Lunar.

This is good enough argument for me.

[lanefu]

removed my /usr/bin/python symlink and worked building rock5 kernel. saw python2 execute