FIx files generated with wrong user id, fixes #627 (#632)

native/docker/crossbuild-uid/Dockerfile

@@ -0,0 +1,11 @@
+FROM multiarch/crossbuild
+RUN cd /tmp; \
+    git clone https://github.com/ncopa/su-exec.git; \
+    cd /tmp/su-exec; \
+    make; \
+    cp su-exec /usr/bin; \
+    rm -Rf /tmp/su-exec
+ENTRYPOINT [ "/usr/bin/crossbuild-uid", "/usr/bin/crossbuild" ]
+CMD ["/bin/bash"]
+WORKDIR /workdir
+COPY crossbuild-uid /usr/bin/crossbuild-uid

native/docker/crossbuild-uid/crossbuild-uid

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+
+# This is the entrypoint script for the dockerfile. Executed in the
+# container at runtime.
+
+export PATH_ORIGIN=$PATH
+export LD_LIBRARY_PATH_ORIGIN=$LD_LIBRARY_PATH
+
+# If we are running docker natively, we want to create a user in the container
+# with the same UID and GID as the user on the host machine, so that any files
+# created are owned by that user. Without this they are all owned by root.
+# The dockcross script sets the BUILDER_UID and BUILDER_GID vars.
+if [[ -n $BUILDER_UID ]] && [[ -n $BUILDER_GID ]]; then
+
+    groupadd -o -g $BUILDER_GID $BUILDER_GROUP 2> /dev/null
+    useradd -o -m -g $BUILDER_GID -u $BUILDER_UID $BUILDER_USER 2> /dev/null
+    export HOME=/home/${BUILDER_USER}
+    shopt -s dotglob
+    cp -r /root/* $HOME/
+    chown -R $BUILDER_UID:$BUILDER_GID $HOME
+
+    # Enable passwordless sudo capabilities for the user
+    chown root:$BUILDER_GID $(which su-exec)
+    chmod +s $(which su-exec); sync
+
+    # Run the command as the specified user/group.
+    exec su-exec $BUILDER_UID:$BUILDER_GID "$@"
+else
+    # Just run the command as root.
+    exec "$@"
+fi