Support clangd version 19 (LLVM-407)

[mrjohannchang]

Checklist

• Checked the issue tracker for similar issues to ensure this is not a duplicate.
• Described the feature in detail and justified the reason for the request.
• Provided specific use cases and examples.

Feature description

C23 will be finalized within a month, most of its features are already available in GCC provided in esp-13.2.0_20240530 that's bundled with ESP-IDF version 5.3. But the support in the current bundled clangd is a bit behind.

Use cases

There are some great features in C23, such as constexpr. This feature can already be used with GCC version 13 bundled in ESP-IDF v5.3. However, since it's not supported until clangd version 19, the bundled clangd does not recognize it, leading to errors on every line that contains this syntax. This results in clangd's error messages becoming excessively verbose.

Alternatives

I can use clangd from standard LLVM 19 instead. But without Espressif's patch, some of the includes will not be identified properly.

Additional context

No response

[gerekon]

Hi @mrjohannchang!

We are finishing rebase our fork on LLVM 19 and plan to do the release which also will include clangd.

[mrjohannchang]

Thank you! I'll close this issue once Espressif's fork is bumped to version 19.