Support for macro_rules! generated functions in csbindgen

[ilinchunjie]

Problem Description

csbindgen currently cannot recognize functions generated through macro_rules! macros, preventing these functions from being included in the generated C# binding code.

• Manually written functions with #[unsafe(no_mangle)] attributes are correctly recognized and generated
• Functions generated through macro_rules! macros (even with the same attributes) cannot be recognized
• Generated C# binding files are missing numerous functions generated by macros

Environment Information

csbindgen version: 1.9.5 Rust version: 2024 edition

[neuecc]

Since it's based on AST analysis, I think it would be difficult to process macros.

[Skgland]

There is the unstable -Zunpretty=expanded which could be used to obtain code with macros already expanded and then csbindgen could analyses that.

cbindgen apparently (used to?) usees that