build a proper c++-enabled musl toolchain with musl-cross-make

src/ci/docker/dist-x86_64-musl/Dockerfile

@@ -4,6 +4,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   g++ \
   make \
   file \
+  wget \
   curl \
   ca-certificates \
   python2.7 \
@@ -18,19 +19,17 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 WORKDIR /build/
 
-COPY scripts/musl.sh /build/
+COPY scripts/musl-toolchain.sh /build/
 # We need to mitigate rust-lang/rust#34978 when compiling musl itself as well
-RUN CC=gcc \
-    CFLAGS="-Wa,-mrelax-relocations=no" \
-    CXX=g++ \
-    CXXFLAGS="-Wa,-mrelax-relocations=no" \
-    bash musl.sh x86_64 && rm -rf /build
+# TODO: Check what this issue is and if we can ignore it
+
+RUN bash musl-toolchain.sh x86_64-linux-musl && rm -rf build
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
 ENV RUST_CONFIGURE_ARGS \
-      --musl-root-x86_64=/musl-x86_64 \
+      --musl-root-x86_64=/usr/local/x86_64-linux-musl \
       --enable-extended \
       --disable-docs
 
@@ -39,9 +38,14 @@ ENV RUST_CONFIGURE_ARGS \
 # way to produce "super compatible" binaries.
 #
 # See: https://github.com/rust-lang/rust/issues/34978
-ENV CFLAGS_x86_64_unknown_linux_musl=-Wa,-mrelax-relocations=no
+#ENV CFLAGS_x86_64_unknown_linux_musl=-Wa,-mrelax-relocations=no
 
-ENV HOSTS=x86_64-unknown-linux-musl
+ENV HOSTS=x86_64-unknown-linux-musl \
+    CC_x86_64_unknown_linux_musl=x86_64-linux-musl-gcc \
+    CXX_x86_64_unknown_linux_musl=x86_64-linux-musl-g++
+
+#    CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_LINKER=musl-gcc \
+#    CARGO_TARGET_ARM_UNKNOWN_LINUX_MUSLEABIHF_RUNNER="qemu-arm -L /musl-arm"
 
 ENV RUSTFLAGS="-C target-feature=-crt-static"
 

src/ci/docker/scripts/musl-toolchain.sh

@@ -0,0 +1,66 @@
+# Copyright 2016 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 -ex
+
+hide_output() {
+  set +x
+  on_err="
+echo ERROR: An error was encountered with the build.
+cat /tmp/build.log
+exit 1
+"
+  trap "$on_err" ERR
+  bash -c "while true; do sleep 30; echo \$(date) - building ...; done" &
+  PING_LOOP_PID=$!
+  $@ &> /tmp/build.log
+  trap - ERR
+  kill $PING_LOOP_PID
+  rm /tmp/build.log
+  set -x
+}
+
+TARGET=$1
+OUTPUT=/usr/local
+shift
+
+git clone https://github.com/richfelker/musl-cross-make -b v0.9.7
+cd musl-cross-make
+
+hide_output make -j$(nproc) TARGET=$TARGET
+hide_output make install TARGET=$TARGET OUTPUT=$OUTPUT
+
+cd ..
+
+export CC=$TARGET-gcc
+export CXX=$TARGET-g++
+
+LLVM=60
+
+# may have been downloaded in a previous run
+if [ ! -d libunwind-release_$LLVM ]; then
+  curl -L https://github.com/llvm-mirror/llvm/archive/release_$LLVM.tar.gz | tar xzf -
+  curl -L https://github.com/llvm-mirror/libunwind/archive/release_$LLVM.tar.gz | tar xzf -
+fi
+
+mkdir libunwind-build
+cd libunwind-build
+cmake ../libunwind-release_$LLVM \
+          -DLLVM_PATH=/build/llvm-release_$LLVM \
+          -DLIBUNWIND_ENABLE_SHARED=0 \
+          -DCMAKE_C_COMPILER=$CC \
+          -DCMAKE_CXX_COMPILER=$CXX \
+          -DCMAKE_C_FLAGS="$CFLAGS" \
+          -DCMAKE_CXX_FLAGS="$CXXFLAGS"
+
+hide_output make -j$(nproc)
+cp lib/libunwind.a $OUTPUT/$TARGET/lib
+cd ../ && rm -rf libunwind-build
+