switch codebuild from clang 7 to clang 8

This is to catch problems as in #4744.

Author: Daniel Kroening

buildspec-linux-clang.yml

@@ -11,20 +11,21 @@ phases:
       java: openjdk8
     commands:
       - sed -i 's#/archive.ubuntu.com#/us-east-1.ec2.archive.ubuntu.com#g' /etc/apt/sources.list
+      - add-apt-repository 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-8 main'
       - apt-get update -y
-      - apt-get install -y clang-7 flex bison make git libwww-perl patch ccache libc6-dev-i386 jq
+      - apt-get install -y clang-8 flex bison make git libwww-perl patch ccache libc6-dev-i386 jq
   build:
     commands:
       - echo Build started on `date`
       - git submodule update --init --recursive
-      - make -C src CXX='ccache /usr/bin/clang++-7' CXX_FLAGS='-Qunused-arguments'
-      - make -C jbmc/src CXX='ccache /usr/bin/clang++-7' CXX_FLAGS='-Qunused-arguments'
+      - make -C src CXX='ccache /usr/bin/clang++-8' CXX_FLAGS='-Qunused-arguments'
+      - make -C jbmc/src CXX='ccache /usr/bin/clang++-8' CXX_FLAGS='-Qunused-arguments'
   post_build:
     commands:
-      - make -C unit test CXX='ccache /usr/bin/clang++-7' CXX_FLAGS='-Qunused-arguments'
+      - make -C unit test CXX='ccache /usr/bin/clang++-8' CXX_FLAGS='-Qunused-arguments'
       - make -C regression test
       - env PATH=$PATH:`pwd`/src/solvers make -C regression/cbmc test-cprover-smt2
-      - make -C jbmc/unit test CXX='ccache /usr/bin/clang++-7' CXX_FLAGS='-Qunused-arguments'
+      - make -C jbmc/unit test CXX='ccache /usr/bin/clang++-8' CXX_FLAGS='-Qunused-arguments'
       - make -C jbmc/regression test
       - echo Build completed on `date`
 cache: