PyOxidizer project build fails due to jemalloc-sys unable to build with toolchain x86_64-unknown-linux-musl

Hi,

I am attempting to build a [fully static binary](https://pyoxidizer.readthedocs.io/en/stable/packaging_static_linking.html?highlight=static#building-fully-statically-linked-binaries-on-linux) using PyOxidizer. But the build fails due to jemalloc-sys not able to build.

Steps to reproduce:
Install musl-tools and musl-dev: $ sudo apt-get install musl-tools musl-dev
Create a new pyoxidizer project $ pyoxidizer init-config-file helloworld
Add musl toolchain: $ rustup target add x86_64-unknown-linux-musl
Build pyoxidizer project against musl toolchain ubuntu@ubuntu:~/helloworld$ RUST_BACKTRACE=1 pyoxidizer build --target-triple x86_64-unknown-linux-musl

Using nightly toolchain also fails with the same error.
Platform is Ubuntu 18.04.

Many thanks in advance.

Reproduce the failure with `RUST_BACKTRACE=1 pyoxidizer build --target-triple x86_64-unknown-linux-musl` after installing musl-tools, musl-dev, and the Rust target. Start by tracing the jemalloc-sys build failure under the musl toolchain; done means the sample project builds successfully for x86_64-unknown-linux-musl, including with the documented static-linking workflow.

Written by the indexing model from the issue text.