Move compilation to root user to resolve permission issues

Dockerfile

@@ -72,12 +72,8 @@ RUN apt-get update && \
 # Static linking for C++ code
 RUN sudo ln -s "/usr/bin/g++" "/usr/bin/musl-g++"
 
-# Allow sudo without a password.
-ADD sudoers /etc/sudoers.d/nopasswd
-
-# Run all further code as user `rust`, and create our working directories
-# as the appropriate user.
-USER rust
+# Create a working directory
+ENV HOME=/home/rust
 RUN mkdir -p /home/rust/libs /home/rust/src
 
 # Set up our path with all our binary directories, including those for the
@@ -91,8 +87,7 @@ ENV PATH=/home/rust/.cargo/bin:/usr/local/musl/bin:/usr/local/sbin:/usr/local/bi
 # manually.
 RUN curl https://sh.rustup.rs -sSf | \
     sh -s -- -y --default-toolchain $TOOLCHAIN && \
-    rustup target add x86_64-unknown-linux-musl && \
-    rustup target add armv7-unknown-linux-musleabihf
+    rustup target add x86_64-unknown-linux-musl
 ADD cargo-config.toml /home/rust/.cargo/config
 
 # Set up a `git credentials` helper for using GH_USER and GH_TOKEN to access
@@ -168,6 +163,5 @@ RUN cargo install -f cargo-audit && \
     cargo install -f mdbook-graphviz && \
     rm -rf /home/rust/.cargo/registry/
 
-# Expect our source code to live in /home/rust/src.  We'll run the build as
-# user `rust`, which will be uid 1000, gid 1000 outside the container.
+# Expect our source code to live in /home/rust/src.
 WORKDIR /home/rust/src

cargo-config.toml

@@ -1,6 +1,3 @@
 [build]
 # Target musl-libc by default when running Cargo.
 target = "x86_64-unknown-linux-musl"
-
-[target.armv7-unknown-linux-musleabihf]
-linker = "arm-linux-gnueabihf-gcc"