Rollup merge of #47427 - EdSchouten:cloudabi-ci, r=alexcrichton

Add a Docker container for doing automated builds for CloudABI.

Setting up a cross compilation toolchain for CloudABI is relatively
easy. It's just a matter of installing a somewhat recent version of
Clang (5.0 preferred) and installing the corresponding
`${target}-cxx-runtime` package, containing a set of core C/C++ libraries
(libc, libc++, libunwind, etc).

Eventually it would be nice if we could also run `x.py test`. That,
however still requires some more work. Both libtest and compiletest
would need to be adjusted to deal with CloudABI's requirement of having
all of an application's dependencies injected. Let's settle for just
doing `x.py dist` for now.

src/ci/docker/dist-various-2/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:16.04
+FROM ubuntu:17.10
 
 COPY scripts/cross-apt-packages.sh /scripts/
 RUN sh /scripts/cross-apt-packages.sh
@@ -21,9 +21,12 @@ RUN apt-key adv --batch --yes --keyserver keyserver.ubuntu.com --recv-keys 74DA7
 RUN add-apt-repository -y 'deb http://apt.dilos.org/dilos dilos2-testing main'
 
 WORKDIR /tmp
-COPY dist-various-2/shared.sh dist-various-2/build-fuchsia-toolchain.sh /tmp/
-COPY dist-various-2/build-solaris-toolchain.sh /tmp/
+COPY dist-various-2/shared.sh /tmp/
+COPY dist-various-2/build-cloudabi-toolchain.sh /tmp/
+RUN /tmp/build-cloudabi-toolchain.sh x86_64-unknown-cloudabi
+COPY dist-various-2/build-fuchsia-toolchain.sh /tmp/
 RUN /tmp/build-fuchsia-toolchain.sh
+COPY dist-various-2/build-solaris-toolchain.sh /tmp/
 RUN /tmp/build-solaris-toolchain.sh x86_64  amd64   solaris-i386
 RUN /tmp/build-solaris-toolchain.sh sparcv9 sparcv9 solaris-sparc
 
@@ -44,12 +47,20 @@ ENV \
     CC_x86_64_sun_solaris=x86_64-sun-solaris2.10-gcc \
     CXX_x86_64_sun_solaris=x86_64-sun-solaris2.10-g++
 
+# FIXME(EdSchouten): Remove this once cc ≥1.0.4 has been merged. It can
+# automatically pick the right compiler path.
+ENV \
+    AR_x86_64_unknown_cloudabi=x86_64-unknown-cloudabi-ar \
+    CC_x86_64_unknown_cloudabi=x86_64-unknown-cloudabi-clang \
+    CXX_x86_64_unknown_cloudabi=x86_64-unknown-cloudabi-clang++
+
 ENV TARGETS=x86_64-unknown-fuchsia
 ENV TARGETS=$TARGETS,aarch64-unknown-fuchsia
 ENV TARGETS=$TARGETS,sparcv9-sun-solaris
 ENV TARGETS=$TARGETS,wasm32-unknown-unknown
 ENV TARGETS=$TARGETS,x86_64-sun-solaris
 ENV TARGETS=$TARGETS,x86_64-unknown-linux-gnux32
+ENV TARGETS=$TARGETS,x86_64-unknown-cloudabi
 
 ENV RUST_CONFIGURE_ARGS --target=$TARGETS --enable-extended
 ENV SCRIPT python2.7 ../x.py dist --target $TARGETS

src/ci/docker/dist-various-2/build-cloudabi-toolchain.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+# Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+# file at the top-level directory of this distribution and at
+# http://rust-lang.org/COPYRIGHT.
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+set -eux
+
+# Install prerequisites.
+apt-get update
+apt-get install -y --no-install-recommends \
+  apt-transport-https \
+  ca-certificates \
+  clang-5.0 \
+  cmake \
+  curl \
+  file \
+  g++ \
+  gdb \
+  git \
+  lld-5.0 \
+  make \
+  python \
+  sudo \
+  xz-utils
+
+# Set up a Clang-based cross compiler toolchain.
+# Based on the steps described at https://nuxi.nl/cloudabi/debian/
+target=$1
+for tool in ar nm objdump ranlib size; do
+  ln -s ../lib/llvm-5.0/bin/llvm-${tool} /usr/bin/${target}-${tool}
+done
+ln -s ../lib/llvm-5.0/bin/clang /usr/bin/${target}-cc
+ln -s ../lib/llvm-5.0/bin/clang /usr/bin/${target}-c++
+ln -s ../lib/llvm-5.0/bin/lld /usr/bin/${target}-ld
+ln -s ../../${target} /usr/lib/llvm-5.0/${target}
+
+# FIXME(EdSchouten): Remove this once cc ≥1.0.4 has been merged. It
+# can make use of ${target}-cc and ${target}-c++, without incorrectly
+# assuming it's MSVC.
+ln -s ../lib/llvm-5.0/bin/clang /usr/bin/${target}-clang
+ln -s ../lib/llvm-5.0/bin/clang /usr/bin/${target}-clang++
+
+# Install the C++ runtime libraries from CloudABI Ports.
+echo deb https://nuxi.nl/distfiles/cloudabi-ports/debian/ cloudabi cloudabi > \
+    /etc/apt/sources.list.d/cloudabi.list
+curl 'https://pgp.mit.edu/pks/lookup?op=get&search=0x0DA51B8531344B15' | \
+    apt-key add -
+apt-get update
+apt-get install -y $(echo ${target} | sed -e s/_/-/g)-cxx-runtime