cargo-n64 xbuild error.txt

$ rustc --version
rustc 1.45.0-nightly (a74d1862d 2020-05-14)

$ cargo xbuild --version
cargo-xbuild 0.5.31

$ cargo n64 build --ipl3 ipl3.bin --package hello-ipl3font --verbose
    Building with cargo xbuild
+ "cargo" "xbuild" "--message-format=json" "--target=/var/folders/j3/7pf540td3xncn7jdqtb62_ph00058y/T/n64-build/mips-nintendo64-none.json" "--package" "hello-ipl3font" "--verbose" "--release"
WARNING: There is no root package to read the cargo-xbuild config from.
+ "rustc" "--print" "sysroot"
+ "rustc" "--print" "target-list"
+ RUSTFLAGS="--sysroot /Users/me/src/cargo-n64/target/sysroot"
+ RUSTDOCFLAGS="--sysroot /Users/me/src/cargo-n64/target/sysroot"
+ "/Users/me/.rustup/toolchains/nightly-2020-05-15-x86_64-apple-darwin/bin/cargo" "build" "--message-format=json" "--target=/var/folders/j3/7pf540td3xncn7jdqtb62_ph00058y/T/n64-build/mips-nintendo64-none.json" "--package" "hello-ipl3font" "--verbose" "--release"
       Fresh n64lib v0.1.0 (/Users/me/src/cargo-n64/examples/n64lib)
       Fresh libm v0.1.4
       Fresh rrt0 v0.1.3
       Fresh hello-ipl3font v0.1.0 (/Users/me/src/cargo-n64/examples/hello-ipl3font)
    Finished release [optimized] target(s) in 0.02s
error: Build error
caused by: Subcommand failed
caused by: JSON error: {"reason":"build-finished","success":true}
caused by: missing field `message` at line 1 column 42