Auto merge of #43129 - Ophirr33:master, r=alexcrichton

Updated docker images to share scripts

Attempts to resolve #42201. I managed to pull out five scripts (android-base-apt-get, ubuntu16-apt-get, make3, rustbuild-setup, and crosstool-ng). Let me know if there's more I can do or if I should change some names.
r? @malbarbo

Author: bors

src/ci/docker/arm-android/Dockerfile

@@ -1,31 +1,15 @@
 FROM ubuntu:16.04
 
-RUN apt-get update && \
-    apt-get install -y --no-install-recommends \
-  ca-certificates \
-  cmake \
-  curl \
-  file \
-  g++ \
-  git \
-  libssl-dev \
-  make \
-  pkg-config \
-  python2.7 \
-  sudo \
-  unzip \
-  xz-utils
-
-# dumb-init
+COPY scripts/android-base-apt-get.sh /scripts/
+RUN sh /scripts/android-base-apt-get.sh
+
 COPY scripts/dumb-init.sh /scripts/
 RUN sh /scripts/dumb-init.sh
 
-# ndk
 COPY scripts/android-ndk.sh /scripts/
 RUN . /scripts/android-ndk.sh && \
     download_and_make_toolchain android-ndk-r13b-linux-x86_64.zip arm 9
 
-# sdk
 RUN dpkg --add-architecture i386 && \
     apt-get update && \
     apt-get install -y --no-install-recommends \
@@ -39,7 +23,6 @@ COPY scripts/android-sdk.sh /scripts/
 RUN . /scripts/android-sdk.sh && \
     download_and_create_avd tools_r25.2.5-linux.zip armeabi-v7a 18
 
-# env
 ENV PATH=$PATH:/android/sdk/tools
 ENV PATH=$PATH:/android/sdk/platform-tools
 
@@ -51,10 +34,8 @@ ENV RUST_CONFIGURE_ARGS \
 
 ENV SCRIPT python2.7 ../x.py test --target $TARGETS
 
-# sccache
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-# init
 COPY scripts/android-start-emulator.sh /scripts/
 ENTRYPOINT ["/usr/bin/dumb-init", "--", "/scripts/android-start-emulator.sh"]

src/ci/docker/armhf-gnu/Dockerfile

@@ -73,13 +73,12 @@ RUN arm-linux-gnueabihf-gcc addentropy.c -o rootfs/addentropy -static
 # TODO: What is this?!
 RUN curl -O http://ftp.nl.debian.org/debian/dists/jessie/main/installer-armhf/current/images/device-tree/vexpress-v2p-ca15-tc1.dtb
 
-RUN curl -o /usr/local/bin/sccache \
-      https://s3.amazonaws.com/rust-lang-ci/rust-ci-mirror/2017-05-12-sccache-x86_64-unknown-linux-musl && \
-      chmod +x /usr/local/bin/sccache
+COPY scripts/dumb-init.sh /scripts/
+RUN sh /scripts/dumb-init.sh
+
+COPY scripts/sccache.sh /scripts/
+RUN sh /scripts/sccache.sh
 
-RUN curl -OL https://github.com/Yelp/dumb-init/releases/download/v1.2.0/dumb-init_1.2.0_amd64.deb && \
-    dpkg -i dumb-init_*.deb && \
-    rm dumb-init_*.deb
 ENTRYPOINT ["/usr/bin/dumb-init", "--"]
 
 ENV RUST_CONFIGURE_ARGS \