cpal Mismatched types cross compiling asio-sys with x86

Hello, trying to cross-compile CPAL with the asio feature from a Linux box to Windows (x86_64-pc-windows-gnu) gives me this compile error

$ cargo build --target x86_64-pc-windows-gnu --features asio
   Compiling asio-sys v0.2.2 (.../Developer/cpal/asio-sys)
error[E0308]: mismatched types
    --> asio-sys/src/bindings/mod.rs:1029:36
     |
1029 |               time.time_info.flags = (ai::AsioTimeInfoFlags::kSystemTimeValid
     |  _____________--------------------___^
     | |             |
     | |             expected due to the type of this binding
1030 | |                 | ai::AsioTimeInfoFlags::kSamplePositionValid)
1031 | |                 // Context about the cast:
1032 | |                 //
...    |
1049 | |                 // } AsioTimeInfoFlags;
1050 | |                 .0;
     | |__________________^ expected `i32`, found `u32`

For more information about this error, try `rustc --explain E0308`.
error: could not compile `asio-sys` (lib) due to 1 previous error

It could be I'm missing something? I'm not sure, cross-compiling can be a bit of a heck. I tried using both cross and without cross to build, with the same error both times - gonna put both ways I've reproduced it below, though they are very similar.

Reproing with cross

Clone CPAL - git clone https://github.com/RustAudio/cpal.git
Edit Cross.toml to add the following lines

[target.x86_64-pc-windows-gnu]
# Needed for unzipping the ASIO SDK
pre-build = [
    "apt-get update && apt-get --assume-yes install unzip",
]

[target.x86_64-pc-windows-gnu.env]
# TODO: Not make assumptions about what version of LLVM the cross image uses
# This is needed so we don't get errors about a missing x86intrin.h header
# I end up getting the same errors using `CPLUS_INCLUDE_PATH` as well instead of `BINDGEN_CLANG_EXTRA_ARGS`
# And trying to use  the MinGW include paths instead of the LLVM one here (/usr/lib/gcc/x86_64-w64-mingw32/7.3-{posix,win32}/include) gives me undefined symbol errors
passthrough = [
    "BINDGEN_CLANG_EXTRA_ARGS=-I/usr/lib/llvm-6.0/lib/clang/6.0.0/include",
]