G_TYPE_FUNDAMENTAL_MAX mimatch

I ran in to this issue when updating the gtk-rs bindings to the 0.6.x release for debian. gobject-sys 0.17.10 fails to cross-validate the constants from C:

running 2 tests
test cross_validate_layout_with_c ... ok
test cross_validate_constants_with_c ... FAILED

failures:

---- cross_validate_constants_with_c stdout ----
Constant value mismatch for G_TYPE_FUNDAMENTAL_MAX
Rust: "255"
C:    "1020"
thread 'cross_validate_constants_with_c' panicked at 'FAILED: 63 passed; 1 failed', tests/abi.rs:109:13
stack backtrace:
   0: rust_begin_unwind
             at /usr/src/rustc-1.66.0/library/std/src/panicking.rs:575:5
   1: core::panicking::panic_fmt
             at /usr/src/rustc-1.66.0/library/core/src/panicking.rs:65:14
   2: abi::Results::expect_total_success
             at ./tests/abi.rs:109:13
   3: abi::cross_validate_constants_with_c
             at ./tests/abi.rs:145:5
   4: abi::cross_validate_constants_with_c::{{closure}}
             at ./tests/abi.rs:115:1
   5: core::ops::function::FnOnce::call_once
             at /usr/src/rustc-1.66.0/library/core/src/ops/function.rs:251:5
   6: core::ops::function::FnOnce::call_once
             at /usr/src/rustc-1.66.0/library/core/src/ops/function.rs:251:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.


failures:
    cross_validate_constants_with_c

test result: FAILED. 1 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.37s

sources.debian.org told me the value for G_TYPE_FUNDAMENTAL_MAX should be 255 (I think).

The gtk-rs maintainers pointed out they also expect 255 in their (rust) code:

    <constant name="TYPE_FUNDAMENTAL_MAX"
              value="255"
              c:type="G_TYPE_FUNDAMENTAL_MAX">

According to them this is a glib issue, so I am reporting it here. Original issue here