[CI] Update dist-x86_64-linux to GCC 5.5

This also updates dist-i686-linux, since it borrows the same scripts.

While we're at it, update llvm+clang+lld to llvm-project 8.0.0-rc2.

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

@@ -4,26 +4,14 @@ set -ex
 
 source shared.sh
 
-# Currently these commits are all tip-of-tree as of 2018-12-16, used to pick up
-# a fix for rust-lang/rust#56849
-LLVM=032b00a5404865765cda7db3039f39d54964d8b0
-LLD=3e4aa4e8671523321af51449e0569f455ef3ad43
-CLANG=a6b9739069763243020f4ea6fe586bc135fde1f9
+LLVM=llvmorg-8.0.0-rc2
 
-mkdir clang
-cd clang
+mkdir llvm-project
+cd llvm-project
 
-curl -L https://github.com/llvm-mirror/llvm/archive/$LLVM.tar.gz | \
+curl -L https://github.com/llvm/llvm-project/archive/$LLVM.tar.gz | \
   tar xzf - --strip-components=1
 
-mkdir -p tools/clang
-curl -L https://github.com/llvm-mirror/clang/archive/$CLANG.tar.gz | \
-  tar xzf - --strip-components=1 -C tools/clang
-
-mkdir -p tools/lld
-curl -L https://github.com/llvm-mirror/lld/archive/$LLD.tar.gz | \
-  tar zxf - --strip-components=1 -C tools/lld
-
 mkdir clang-build
 cd clang-build
 
@@ -39,20 +27,21 @@ cd clang-build
 #
 # [1]: https://sourceware.org/ml/crossgcc/2008-11/msg00028.html
 INC="/rustroot/include"
-INC="$INC:/rustroot/lib/gcc/x86_64-unknown-linux-gnu/4.8.5/include-fixed"
+INC="$INC:/rustroot/lib/gcc/x86_64-unknown-linux-gnu/5.5.0/include-fixed"
 INC="$INC:/usr/include"
 
 hide_output \
-    cmake .. \
+    cmake ../llvm \
       -DCMAKE_C_COMPILER=/rustroot/bin/gcc \
       -DCMAKE_CXX_COMPILER=/rustroot/bin/g++ \
       -DCMAKE_BUILD_TYPE=Release \
       -DCMAKE_INSTALL_PREFIX=/rustroot \
       -DLLVM_TARGETS_TO_BUILD=X86 \
+      -DLLVM_ENABLE_PROJECTS="clang;lld" \
       -DC_INCLUDE_DIRS="$INC"
 
 hide_output make -j10
 hide_output make install
 
 cd ../..
-rm -rf clang
+rm -rf llvm-project

src/ci/docker/dist-x86_64-linux/build-gcc.sh

@@ -3,9 +3,9 @@ set -ex
 
 source shared.sh
 
-GCC=4.8.5
+GCC=5.5.0
 
-curl https://ftp.gnu.org/gnu/gcc/gcc-$GCC/gcc-$GCC.tar.bz2 | tar xjf -
+curl https://ftp.gnu.org/gnu/gcc/gcc-$GCC/gcc-$GCC.tar.xz | xzcat | tar xf -
 cd gcc-$GCC
 
 # FIXME(#49246): Remove the `sed` below.

src/ci/docker/dist-x86_64-linux/build-perl.sh

@@ -11,7 +11,8 @@ cd perl-5.28.0
 # Gotta do some hackery to tell python about our custom OpenSSL build, but other
 # than that fairly normal.
 CC=gcc \
-CFLAGS='-I /rustroot/include' LDFLAGS='-L /rustroot/lib -L /rustroot/lib64' \
+CFLAGS='-I /rustroot/include -fgnu89-inline' \
+LDFLAGS='-L /rustroot/lib -L /rustroot/lib64' \
     hide_output ./configure.gnu
 hide_output make -j10
 hide_output make install