Automatically add rom_functions.x to the linker scripts

[bjoernQ]

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Submission Checklist 📝

• I have updated existing examples or added new ones (if applicable).
• I have used cargo xtask fmt-packages command to ensure that all changed code is formatted correctly.
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Pull Request Details 📖

Description

Don't require users to manually add rom_functions.x when using esp-wifi

esp-hal now includes a (private) feature to do that. It's automatically activated by esp-wifi since we depend on esp-hal anyways

skip-changelog because of the added private feature in esp-hal

Testing

Examples still work. Apparently adding it manually in addition is not a problem (for lld .... but it is for gnu-ld)

[bjoernQ]

I guess the failing HIL test is unrelated to this PR

[bugadani]

Do we want to keep these on incompatible devices?

[bjoernQ]

Given it's an internal feature my thinking was it's doesn't need additional safety belts - we could certainly check it in build.rs if we think we should

[bjoernQ]

T.b.h long term we should change esp-wifi-sys to include all rom functions via rom_functions.x but maybe when we have some more interesting reasons to justify a new version

[Sycrosity]

This is a nice QOL change! I've been manually added build.rs scripts to avoid .cargo/config.toml files with the current system.

[MabezDev]

What about if all the linker scripts lived in esp-hal? For instance, rom-functions.x definitely could and would save an internal feature here - not sure about the phy or coexist linker files though

[bjoernQ]

What about if all the linker scripts lived in esp-hal? For instance, rom-functions.x definitely could and would save an internal feature here - not sure about the phy or coexist linker files though

They all definitely could - one annoyance is when updating drivers we might need to change them since it often happens that ROM functions are replaced by the libraries (and apparently just defining them weak would cause problems)

[bjoernQ]

Thinking about it - yes let's do that. We just need to make sure we are in sync with what commit the drivers are from - shouldn't be a huge problem