mio: Linking fails with x86_64-pc-windows-gnu toolchain

Mio defines NtCancelIoFileEx as follows:

#[link(name = "ntdll")]
extern "system" {
    /// See <https://processhacker.sourceforge.io/doc/ntioapi_8h.html#a0d4d550cad4d62d75b76961e25f6550c>
    ///
    /// This is an undocumented API and as such not part of <https://github.com/microsoft/win32metadata>
    /// from which `windows-sys` is generated, and also unlikely to be added, so
    /// we manually declare it here
    fn NtCancelIoFileEx(
        FileHandle: HANDLE,
        IoRequestToCancel: *mut IO_STATUS_BLOCK,
        IoStatusBlock: *mut IO_STATUS_BLOCK,
    ) -> NTSTATUS;
}

If I add fn main(){} and build with cargo build I get the following linker error:

error: linking with `x86_64-w64-mingw32-gcc` failed: exit code: 1
  |
  = note: "x86_64-w64-mingw32-gcc" "-fno-use-linker-plugin" "-Wl,--dynamicbase" "-Wl,--disable-auto-image-base" "-m64" "-Wl,--high-entropy-va" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\self-contained\\crt2.o" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\rsbegin.o" "C:\\Users\\eiderdaus\\AppData\\Local\\Temp\\rustcJSg3zJ\\symbols.o" "C:\\foo\\target\\debug\\deps\\foo-cb89f6e868929cf3.1bc41oyhwfcqyo6z.rcgu.o" "C:\\foo\\target\\debug\\deps\\foo-cb89f6e868929cf3.2e77gpka6erk4c1x.rcgu.o" "C:\\foo\\target\\debug\\deps\\foo-cb89f6e868929cf3.3wy12xbuznp9hor0.rcgu.o" "C:\\foo\\target\\debug\\deps\\foo-cb89f6e868929cf3.4f95o7n55leh2ke1.rcgu.o" "C:\\foo\\target\\debug\\deps\\foo-cb89f6e868929cf3.4rbije3ghxyb129a.rcgu.o" "C:\\foo\\target\\debug\\deps\\foo-cb89f6e868929cf3.53992k6tesbub9hu.rcgu.o" "-L" "C:\\foo\\target\\debug\\deps" "-L" "C:\\Users\\eiderdaus\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\windows_x86_64_gnu-0.42.0\\lib" "-L" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib" "-lntdll" "-Wl,-Bstatic" "C:\\foo\\target\\debug\\deps\\libwindows_sys-87741728b4e67991.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libstd-583b0c1a8d918e48.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libpanic_unwind-32bbe0f97d4b5e74.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libobject-b4abf79acd3cfd5f.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libmemchr-01a39e8be25b0a33.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libaddr2line-4741964b98a78b52.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libgimli-ca9aa9ad07d84224.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\librustc_demangle-77da45e82831415d.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libstd_detect-6b504ee3232db397.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libhashbrown-f23e5590b13d2ba1.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libminiz_oxide-707623ebc84f4938.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libadler-6c1f623f129f8c4e.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\librustc_std_workspace_alloc-b83298f4db169fa7.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libunwind-24a266989a087673.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libcfg_if-451066e352fc52df.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\liblibc-f0b9b386ac2b1f89.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\liballoc-aecd3bcc2854e359.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\librustc_std_workspace_core-295042be5ab55e2d.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libcore-427c90bb0249ec1c.rlib" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libcompiler_builtins-efeda5f809566e63.rlib" "-Wl,-Bdynamic" "-lwindows" "-lkernel32" "-ladvapi32" "-luserenv" "-lkernel32" "-lws2_32" "-lbcrypt" "-lgcc_eh" "-l:libpthread.a" "-lmsvcrt" "-lmingwex" "-lmingw32" "-lgcc" "-lmsvcrt" "-luser32" "-lkernel32" "-Wl,--nxcompat" "-nostartfiles" "-L" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib" "-L" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\self-contained" "-o" "C:\\foo\\target\\debug\\deps\\foo-cb89f6e868929cf3.exe" "-Wl,--gc-sections" "-no-pie" "-nodefaultlibs" "C:\\Users\\eiderdaus\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\rsend.o"
  = note: ld: cannot find -lntdll


warning: `foo` (bin "foo") generated 1 warning
error: could not compile `foo` due to previous error; 1 warning emitted

Compiling the example from README.md fails with the same error (only with more dependencies in the linker command) and so does my Tokio-dependent application.

The reason is obviously #[link(name = "ntdll")]. There’s no libntdll.a in my %USERPROFILE%\.rustup\toolchains\stable-x86_64-pc-windows-gnu\lib\rustlib\x86_64-pc-windows-gnu\lib\self-contained folder.

The windows-sys crate for example also provides some functions from ntdll.dll but those are annotated with link(name = “windows”) and they provide their own libwindows.a. This works flawlessly for me. winapi-rs provides libwindows_ntdll.a in addition to many other libraries but it doesn’t actually provide any functions from ntdll.dll (I think).

I am using Windows 10 and just reinstalled Rust freshly via Rustup, changing only the platform tuple to x86_64-pc-windows-gnu and leaving all other defaults alone. I am uncertain which version of Rust or mio introduced this issue. I only found out when I wanted to recompile a Tokio-dependent project which still worked a few months ago at least.