We use the tree-sitter[1] for parsing C declarations in Rizin[2] (see the "td" command, for example). See our custom grammar[3] (modified mainstream tree-sitter-c). The custom grammar was sadly necessary, due to the inability of Tree-Sitter to have the alternate roots[4].
P.S. Please add a license for your code.
[1] https://tree-sitter.github.io/
[2] https://github.com/rizinorg/rizin/tree/dev/librz/type/parser