ci: Add .travis.yml for trusty

Build with gcc-5 (whatever the ubuntu toolchain ppa uses - currently
gcc-5.2), gcc-4.9 and clang-3.7.

Instead of adding everything into the yml file, I've split off most of
the work into a separate shell script. It's easier to maintain and
extend that way, and Travis CI also recommends to do it this way.

.travis.yml

@@ -0,0 +1,23 @@
+language: cpp
+
+sudo: required
+dist: trusty
+
+matrix:
+  include:
+# Version 5 seems to be whatever is latest - for now it's 5.2
+    - env: VERSION=5
+      compiler: gcc
+      os: linux
+    - env: VERSION=4.9
+      compiler: gcc
+      os: linux
+    - env: VERSION=3.7
+      compiler: clang
+      os: linux
+
+before_install:
+  - ./travis.sh before_install
+
+script:
+  - ./travis.sh script

travis.sh

@@ -0,0 +1,79 @@
+#!/bin/sh
+
+set -ex
+
+linux_before_install() {
+	# Build worker is 64-bit only by default it seems.
+	sudo dpkg --add-architecture i386
+
+	# Compilers
+	if [ "${CXX}" = "clang++" ]; then
+		sudo apt-key adv --fetch-keys http://llvm.org/apt/llvm-snapshot.gpg.key
+		sudo add-apt-repository -y "deb http://llvm.org/apt/trusty/ llvm-toolchain-trusty-${VERSION} main"
+		# g++-4.8-multilib is necessary for compiler dependencies. Well, I think
+		# the specific dependency is probably lib32gcc-4.8-dev.
+		COMPILER_PACKAGE="clang-${VERSION} g++-4.8-multilib"
+	fi
+	if [ "${CXX}" = "g++" ]; then
+		sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
+		COMPILER_PACKAGE="g++-${VERSION}-multilib"
+	fi
+
+	sudo apt-get -qq update
+
+	# The 64-bit versions of the first 7 dependencies are part of the initial
+	# build image. libgtk2.0-dev:i386 and libsdl2-dev:i386 require the 32-bit
+	# versions of the dependencies, and the 2 versions conflict. So those
+	# dependencies must be explicitly installed.
+	sudo apt-get -qq -y install \
+		gir1.2-freedesktop:i386 \
+		gir1.2-gdkpixbuf-2.0:i386 \
+		gir1.2-glib-2.0:i386 \
+		libcairo2-dev:i386 \
+		libgdk-pixbuf2.0-dev:i386 \
+		libgirepository-1.0-1:i386 \
+		libglib2.0-dev:i386 \
+		libaio-dev:i386 \
+		libasound2-dev:i386 \
+		libgl1-mesa-dev:i386 \
+		libgtk2.0-dev:i386 \
+		liblzma-dev:i386 \
+		libpng12-dev:i386 \
+		libsdl2-dev:i386 \
+		libsoundtouch-dev:i386 \
+		libwxgtk3.0-dev:i386 \
+		libxext-dev:i386 \
+		portaudio19-dev:i386 \
+		zlib1g-dev:i386 \
+		${COMPILER_PACKAGE}
+
+	# libpng++-dev is noarch but doesn't install nicely.
+	apt-get download libpng++-dev
+	sudo dpkg --force-all -i $(ls | grep 'libpng++-dev')
+}
+
+linux_script() {
+	mkdir build
+	cd build
+
+	export CC=${CC}-${VERSION} CXX=${CXX}-${VERSION}
+	cmake \
+		-DCMAKE_TOOLCHAIN_FILE=cmake/linux-compiler-i386-multilib.cmake \
+		-DCMAKE_BUILD_TYPE=Release \
+		-DBUILD_REPLAY_LOADERS=TRUE \
+		-DCMAKE_BUILD_PO=FALSE \
+		..
+
+	# Documentation says 1.5 cores, so 2 or 3 threads should work ok.
+	make -j3 install
+}
+
+# Just in case I do manual testing and accidentally insert "rm -rf /"
+case "${1}" in
+before_install|script)
+	${TRAVIS_OS_NAME}_${1}
+	;;
+*)
+	echo "Unknown command" && false
+	;;
+esac