Rollup merge of rust-lang#55952 - michaelwoerister:newer-clang, r=alexcrichton

Update to Clang 7 on CI.

Handles Linux and macOS. Windows seems to already have been updated.

r? @Mark-Simulacrum
cc @rust-lang/infra

Author: pietroalbini

Diff for: .travis.yml

@@ -227,9 +227,9 @@ install:
             chmod +x /usr/local/bin/sccache &&
           travis_retry curl -fo /usr/local/bin/stamp https://s3-us-west-1.amazonaws.com/rust-lang-ci2/rust-ci-mirror/2017-03-17-stamp-x86_64-apple-darwin &&
             chmod +x /usr/local/bin/stamp &&
-          travis_retry curl -f http://releases.llvm.org/6.0.0/clang+llvm-6.0.0-x86_64-apple-darwin.tar.xz | tar xJf - &&
-            export CC=`pwd`/clang+llvm-6.0.0-x86_64-apple-darwin/bin/clang &&
-            export CXX=`pwd`/clang+llvm-6.0.0-x86_64-apple-darwin/bin/clang++ &&
+          travis_retry curl -f http://releases.llvm.org/7.0.0/clang+llvm-7.0.0-x86_64-apple-darwin.tar.xz | tar xJf - &&
+            export CC=`pwd`/clang+llvm-7.0.0-x86_64-apple-darwin/bin/clang &&
+            export CXX=`pwd`/clang+llvm-7.0.0-x86_64-apple-darwin/bin/clang++ &&
             export AR=ar
           ;;
     esac

Diff for: src/ci/docker/dist-i686-linux/Dockerfile

@@ -67,7 +67,7 @@ RUN ./build-gcc.sh
 COPY dist-x86_64-linux/build-python.sh /tmp/
 RUN ./build-python.sh
 
-# Now build LLVM+Clang 6, afterwards configuring further compilations to use the
+# Now build LLVM+Clang 7, afterwards configuring further compilations to use the
 # clang/clang++ compilers.
 COPY dist-x86_64-linux/build-clang.sh /tmp/
 RUN ./build-clang.sh

Diff for: src/ci/docker/dist-x86_64-linux/Dockerfile

@@ -67,7 +67,7 @@ RUN ./build-gcc.sh
 COPY dist-x86_64-linux/build-python.sh /tmp/
 RUN ./build-python.sh
 
-# Now build LLVM+Clang 6, afterwards configuring further compilations to use the
+# Now build LLVM+Clang 7, afterwards configuring further compilations to use the
 # clang/clang++ compilers.
 COPY dist-x86_64-linux/build-clang.sh /tmp/
 RUN ./build-clang.sh

Diff for: src/ci/docker/dist-x86_64-linux/build-clang.sh

@@ -13,7 +13,7 @@ set -ex
 
 source shared.sh
 
-LLVM=6.0.0
+LLVM=7.0.0
 
 mkdir clang
 cd clang

Diff for: src/ci/docker/scripts/musl.sh

@@ -51,7 +51,7 @@ hide_output make clean
 
 cd ..
 
-LLVM=60
+LLVM=70
 
 # may have been downloaded in a previous run
 if [ ! -d libunwind-release_$LLVM ]; then