Add clang to Travis configurations

This adds the clang compiler to the tested Travis configurations.

.ci/Dockerfile-arch-latest

@@ -1,6 +1,9 @@
 FROM archimg/base-devel:latest
 
+ARG toolchain
+
 RUN pacman -Sy
 RUN pacman -S --noconfirm boost cmake git ninja re2c
+RUN if [ "${toolchain}" = "clang" ]; then pacman -S --noconfirm clang; fi
 
 VOLUME /app

.ci/Dockerfile-ubuntu-18.04

@@ -1,6 +1,9 @@
 FROM ubuntu:18.04
 
+ARG toolchain
+
 RUN apt-get update
 RUN apt-get install -y libboost-all-dev cmake git ninja-build re2c
+RUN if [ "${toolchain}" = "clang" ]; then apt-get install -y clang; fi
 
 VOLUME /app

.ci/ci.sh

@@ -1,7 +1,17 @@
 #!/bin/bash
 
+if [ "$1" = "gcc" ]
+then
+	cxx=g++
+	cc=gcc
+elif [ "$1" = "clang" ]
+then
+	cxx=clang++
+	cc=clang
+fi
+
 git submodule update --init --recursive
 mkdir -p build/debug
 cd build/debug
-cmake ../.. -GNinja -DANTHEM_BUILD_TESTS=ON
+cmake ../.. -GNinja -DANTHEM_BUILD_TESTS=ON -DCMAKE_CXX_COMPILER=${cxx} -DCMAKE_C_COMPILER=${cc}
 ninja anthem-app && ninja run-tests

.travis.yml

@@ -5,15 +5,21 @@ services:
 
 matrix:
   include:
-    - env: distribution=arch-latest
+    - env: distribution=arch-latest toolchain=gcc
       os: linux
       language: cpp
-    - env: distribution=ubuntu-18.04
+    - env: distribution=arch-latest toolchain=clang
+      os: linux
+      language: cpp
+    - env: distribution=ubuntu-18.04 toolchain=gcc
+      os: linux
+      language: cpp
+    - env: distribution=ubuntu-18.04 toolchain=clang
       os: linux
       language: cpp
 
 before_install:
-  - docker build -t ${distribution} - < .ci/Dockerfile-${distribution}
+  - docker build --build-arg toolchain=${toolchain} -t ${distribution} - < .ci/Dockerfile-${distribution}
 
 script:
-  - docker run --mount source=$(pwd),target=/app,type=bind -w /app ${distribution} /bin/bash -c ".ci/ci.sh"
+  - docker run --mount source=$(pwd),target=/app,type=bind -w /app ${distribution} /bin/bash -c ".ci/ci.sh ${toolchain}"