.travis.yml: Use an explicitly defined build matrix. (#544)

* .travis.yml: Use an explicitly defined build matrix.

* Attempt to use GCC on Mac.

* Add gcc4.8 to Travis deps.

* Remove gcc set from .travis.yml.

* .travis-deps: Install and set compiler to GCC only if we need it.

* Formatting

* Remove redundancy

* .travis.yml: source the deps script.

.travis-deps.sh

@@ -2,6 +2,11 @@
 if [ $TRAVIS_OS_NAME = "osx" ]; then
 	brew update
 	brew install qt5 ffmpeg imagemagick sdl2 libzip libpng
+	if [ "$CC" == "gcc" ]; then
+		brew install gcc@4.9
+		export CC=gcc-4.9
+		export CXX=g++-4.9
+	fi
 else
 	sudo apt-get clean
 	sudo apt-get update

.travis.yml

@@ -1,16 +1,19 @@
-os:
-  - linux
-  - osx
-
 language: c
-compiler:
-  - gcc
-  - clang
-
 sudo: required
-dist: trusty
+matrix:
+  include:
+    - os: linux
+      dist: trusty
+      compiler: clang
+    - os: linux
+      dist: trusty
+      compiler: gcc
+    - os: osx
+      compiler: clang
+    - os: osx
+      compiler: gcc
 
 before_install:
-  - ./.travis-deps.sh
+  - source ./.travis-deps.sh
 
 script: mkdir build && cd build && cmake -DCMAKE_PREFIX_PATH=/usr/local/opt/qt5 .. && make