cargo-xwin panics when building inside a dockerfile

[jaysonsantos]

Hey there, while building an image to build windows binaries I've faced a panic when xwin tries to splat files.

With this Dockerfile you can reproduce the error:

FROM rust:1.65

ENV XWIN_VERSION 'v0.14.3'
ENV XWIN_URL "https://github.com/rust-cross/cargo-xwin/releases/download/${XWIN_VERSION}/cargo-xwin-${XWIN_VERSION}.x86_64-unknown-linux-musl.tar.gz"
ENV XWIN_VERSION 17
ENV XWIN_ARCH x86_64

RUN apt update && apt install -y curl clang pkg-config && rm -rf /var/lib/apt/lists/*
RUN curl -sL "${XWIN_URL}" | tar xz -C /usr/local/bin && chmod 755 /usr/local/bin/cargo-xwin


RUN rustup target add x86_64-pc-windows-msvc \
    && rustup component add clippy llvm-tools-preview \
    && rustup toolchain install nightly -c rustfmt --profile minimal

RUN cd $(mktemp -d) && cargo new download && cd download && cargo xwin build --target x86_64-pc-windows-msvc --release && cd .. && rm $PWD

When cargo xwin starts, after a while it will crash with the following message:

#0 0.902      Created binary (application) `download` package
#0 126.8 thread 'main' panicked at 'already have /root/.cache/cargo-xwin/xwin/sdk/include/um/appnotify.h matching /root/.cache/cargo-xwin/xwin/sdk/include/um/appnotify.h', /root/.cargo/registry/src/github.com-1ecc6299db9ec823/xwin-0.2.12/src/splat.rs:641:17