Docker build fails on OSX

Created by: adrianbrink

Reproduction: Follow the steps in the docker/ on OSX.

Expected behavior: README steps work

Actual behavior: Error

Run this on OSX.

docker build --build-arg LOCAL_UID="$(id -u)" --build-arg LOCAL_GID="$(id -g)" \
    -t redox docker/

Output:

The following NEW packages will be installed:
  x86-64-unknown-redox-binutils x86-64-unknown-redox-gcc
  x86-64-unknown-redox-newlib
0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 33.5 MB of archives.
After this operation, 157 MB of additional disk space will be used.
Get:1 https://static.redox-os.org/toolchain/apt  x86-64-unknown-redox-binutils 0.0.1build611 [2165 kB]
Get:2 https://static.redox-os.org/toolchain/apt  x86-64-unknown-redox-newlib 0.0.2build611 [478 kB]
Get:3 https://static.redox-os.org/toolchain/apt  x86-64-unknown-redox-gcc 0.0.1build611 [30.8 MB]
debconf: delaying package configuration, since apt-utils is not installed
Fetched 33.5 MB in 22s (1467 kB/s)
Selecting previously unselected package x86-64-unknown-redox-binutils.
(Reading database ... 16679 files and directories currently installed.)
Preparing to unpack .../x86-64-unknown-redox-binutils_0.0.1build611_amd64.deb ...
Unpacking x86-64-unknown-redox-binutils (0.0.1build611) ...
Selecting previously unselected package x86-64-unknown-redox-newlib.
Preparing to unpack .../x86-64-unknown-redox-newlib_0.0.2build611_amd64.deb ...
Unpacking x86-64-unknown-redox-newlib (0.0.2build611) ...
Selecting previously unselected package x86-64-unknown-redox-gcc.
Preparing to unpack .../x86-64-unknown-redox-gcc_0.0.1build611_amd64.deb ...
Unpacking x86-64-unknown-redox-gcc (0.0.1build611) ...
Processing triggers for libc-bin (2.24-9ubuntu2.2) ...
Setting up x86-64-unknown-redox-newlib (0.0.2build611) ...
Setting up x86-64-unknown-redox-binutils (0.0.1build611) ...
Setting up x86-64-unknown-redox-gcc (0.0.1build611) ...
Processing triggers for libc-bin (2.24-9ubuntu2.2) ...
groupadd: GID '20' already exists
The command '/bin/sh -c apt-get update       && apt-get install -y dirmngr git gosu gcc fuse nasm qemu-utils pkg-config              libfuse-dev make curl wget file sudo apt-transport-https autoconf flex              bison texinfo       && apt-key adv --keyserver keyserver.ubuntu.com --recv-keys AA12E97F0881517F       && echo "deb https://static.redox-os.org/toolchain/apt/ /" >> /etc/apt/sources.list.d/redox.list       && apt-get update -o Dir::Etc::sourcelist="redox.list"       && apt-get install -y x86-64-unknown-redox-newlib x86-64-unknown-redox-binutils x86-64-unknown-redox-gcc       && groupadd -g $BUILD_GID user       && useradd --shell /bin/bash -u $BUILD_UID -g $BUILD_GID -o -c "" -m $USER       && echo "$USER ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/user-no-sudo-password' returned a non-zero code: 4

Output of

id -g => 20
id -u => 501

Any help on how to get Redox to build on OSX would be appreciated.