Bindgen generates different type name for va_list on different systems

Input C/C++ Header

typedef __builtin_va_list va_list;
void foo(va_list arg);

Bindgen Invocation

$ bindgen input.h

Actual Results

• on arm64 macos

/* automatically generated by rust-bindgen 0.68.1 */

pub type va_list = __builtin_va_list;
extern "C" {
    pub fn foo(arg: va_list);
}
pub type __builtin_va_list = *mut ::std::os::raw::c_char;

• on x64_64 linux

/* automatically generated by rust-bindgen 0.68.1 */

pub type va_list = __builtin_va_list;
extern "C" {
    pub fn foo(arg: *mut __va_list_tag);
}
pub type __builtin_va_list = [__va_list_tag; 1usize];
#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct __va_list_tag {
    pub gp_offset: ::std::os::raw::c_uint,
    pub fp_offset: ::std::os::raw::c_uint,
    pub overflow_arg_area: *mut ::std::os::raw::c_void,
    pub reg_save_area: *mut ::std::os::raw::c_void,
}

Expected Results

I expect the name of this type to be the same on both systems regardless of the underlying implementation.

Start with the input.h example and run bindgen input.h on arm64 macOS and x86_64 Linux to reproduce the differing va_list output. Compare the generated bindings and define completion as producing the same type name on both systems without losing the underlying ABI representation.