Cannot build or install bootloader package due to duplicate llvm-tools dependency within bootloader Cargo.toml

I'm trying to set up a basic skeleton for a Rust-based OS using this package to create a bootloader and boot image, and am running into the following problem:

$ cargo install bootloader --all-features
    Updating crates.io index
  Installing bootloader v0.10.11
error: failed to compile `bootloader v0.10.11`, intermediate artifacts can be found at `/tmp/cargo-installOtF7pN`

Caused by:
  the crate `bootloader v0.10.11` depends on crate `llvm-tools v0.1.1` multiple times with different names

I've also tried just setting bootloader v0.10.11 as a dependency for my crate and trying to build a minimal kernel (just a _start that loops forever and a panic handler) and run into the same issue when trying to build it:

$ cargo build
error: the crate `bootloader v0.10.11` depends on crate `llvm-tools v0.1.1` multiple times with different names

I am using the nightly toolchain via rustup, and have installed the llvm-tools-preview component for the nightly toolchain. Did I miss an important step somewhere? Any ideas?

Inspect the bootloader Cargo.toml and reproduce the failure with cargo install bootloader --all-features or a minimal dependent crate using cargo build. Trace the two llvm-tools v0.1.1 dependencies with different names, then confirm the duplicate-dependency error is gone and the bootloader package builds successfully.