Store parse status of all declarations

[dschrempf]

We get a CI error: https://github.com/well-typed/hs-bindgen/actions/runs/18343147007/job/52243182474?pr=1192

anonymous declaration without tag kind: (unnamed at /usr/include/x86_64-linux-gnu/bits/cmathcalls.h:130:1)

I can not reproduce the error locally, I think because I am using a newer version of LLVM.

Will close

• Record parse status for all declarations #1028
• Introduce SelectedButUnavailable message #1037
• Probably replace SelectDeclMeta with DeclMeta #1038
• Select pass panics when transitive dependencies are declarations that we did not attempt to parse #1178

Finally, this PR is ready for discussion:

• CI failure (not reproducible locally, LLVM version?): Conversion to QualPrelimDeclId fails. -> Moved to separate issue Investigate CI issue with LLVM 15 and anonymous declarations of ordinary type #1220.
• Similarly: Panic due to anonymous declaration without use site in Select pass.
• Do we want to check for unavailableTransitiveDeps?
• DeclIndex: Assembly is complicated.
• DeclIndex: For failures, we do not overwrite existing, previously inserted key-value pairs.
• Binding specifications: Should we also lookup failed parses?
• Binding specifications: We still emit (Error?) traces when replacing declarations.

EDIT: This PR does not yet solve #1037, there is more work to do (we have to find declarations that we fail to generate bindings for because transitive dependencies are unavailable).

[dschrempf]

This PR will be parked for a while, see #1028 (comment).

[dschrempf]

In agreement with Edsko, I am putting this on the queue. Two issues are still unresolved:

• Investigate CI issue with LLVM 15 and anonymous declarations of ordinary type #1220
• Introduce SelectedButUnavailable message #1037