Make travis do all the builds again

Travis was only using the last env section, not merged them and was only doing
one build using gcc instead of six builds (gcc, clang, mingw, ..).

.travis.yml

@@ -1,15 +1,19 @@
 language: c
 
 env:
-  # standard builds
-  - CC=gcc
-  - CC=clang
-  # extra libs
-  - CC=gcc USE_CODEC_VORBIS=1 USE_FREETYPE=1
-  - CC=clang USE_CODEC_VORBIS=1 USE_FREETYPE=1
-  # cross-compile using mingw
-  - CC= PLATFORM="mingw32" ARCH="x86"
-  - CC= PLATFORM="mingw32" ARCH="x86_64"
+  global:
+    # coverity token
+    - secure: "a2pGsG/+LS12sD/vgCF912TKBDDiT8PwRTH50eE94trQoHmD+bubIc4mXR9rSuU/NKNPdn6KZlqrVkVuoIanjYaf+rg28VavGMcBrtVO2cI1yjTUxb5Eq/cT20m3KfZCSFw3iWXfiK1CpDkm9Pdrr2Yz99EGZse3Y6jRGJ6giWM="
+  matrix:
+    # standard builds
+    - CC=gcc
+    - CC=clang
+    # extra libs
+    - CC=gcc USE_CODEC_VORBIS=1 USE_FREETYPE=1
+    - CC=clang USE_CODEC_VORBIS=1 USE_FREETYPE=1
+    # cross-compile using mingw
+    - CC= PLATFORM="mingw32" ARCH="x86"
+    - CC= PLATFORM="mingw32" ARCH="x86_64"
 
 script: ./travis-ci-build.sh
 
@@ -22,10 +26,6 @@ before_install:
 notifications:
   email: false
 
-env:
-  global:
-    - secure: "a2pGsG/+LS12sD/vgCF912TKBDDiT8PwRTH50eE94trQoHmD+bubIc4mXR9rSuU/NKNPdn6KZlqrVkVuoIanjYaf+rg28VavGMcBrtVO2cI1yjTUxb5Eq/cT20m3KfZCSFw3iWXfiK1CpDkm9Pdrr2Yz99EGZse3Y6jRGJ6giWM="
-
 addons:
   coverity_scan:
     project: