travis-ci: clang and gcc are the same on osx and xcode6.3 does not works

.travis.yml

@@ -6,8 +6,8 @@ matrix:
     include:
         - os: linux
           compiler: gcc
+          #gcc (Ubuntu 4.8.4-2ubuntu1~14.04) 4.8.4
         - os: linux
-          compiler: gcc
           addons:
             apt:
               sources:
@@ -19,9 +19,9 @@ matrix:
               - libgl1-mesa-dev
               - libgme-dev
               - p7zip-full
-          env: _CC=gcc-4.8
+          compiler: gcc-4.8
+          #gcc-4.8 (Ubuntu 4.8.5-2ubuntu1~14.04.1) 4.8.5
         - os: linux
-          compiler: gcc
           addons:
             apt:
               sources:
@@ -33,9 +33,9 @@ matrix:
               - libgl1-mesa-dev
               - libgme-dev
               - p7zip-full
-          env: _CC=gcc-4.9
+          compiler: gcc-4.9
+          #gcc-4.9 (Ubuntu 4.9.3-8ubuntu2~14.04) 4.9.3
         - os: linux
-          compiler: gcc
           addons:
             apt:
               sources:
@@ -47,9 +47,9 @@ matrix:
               - libgl1-mesa-dev
               - libgme-dev
               - p7zip-full
-          env: _CC=gcc-5
+          compiler: gcc-5
+          #gcc-5 (Ubuntu 5.3.0-3ubuntu1~14.04) 5.3.0 20151204
         - os: linux
-          compiler: gcc
           addons:
             apt:
               sources:
@@ -61,57 +61,33 @@ matrix:
               - libgl1-mesa-dev
               - libgme-dev
               - p7zip-full
-          env: _CC=gcc-6
+          compiler: gcc-7
+          #gcc-6 (Ubuntu 6.1.1-3ubuntu11~14.04.1) 6.1.1 20160511
         - os: linux
           compiler: clang
+          #clang version 3.5.0 (tags/RELEASE_350/final)
         - os: osx
           osx_image: beta-xcode6.1
-          compiler: gcc
-        - os: osx
-          osx_image: beta-xcode6.1
-          compiler: clang
+          #Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn)
         - os: osx
           osx_image: beta-xcode6.2
-          compiler: gcc    
-        - os: osx
-          osx_image: beta-xcode6.2
-          compiler: clang#
-        - os: osx
-          osx_image: beta-xcode6.3
-          compiler: gcc
-        - os: osx
-          osx_image: beta-xcode6.3
-          compiler: clang
-        - os: osx
-          osx_image: xcode6.4
           compiler: gcc
+          #Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn)
         - os: osx
           osx_image: xcode6.4
-          compiler: clang
+          #Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
         - os: osx
           osx_image: xcode7
-          compiler: gcc
-        - os: osx
-          osx_image: xcode7
-          compiler: clang
+          #Apple LLVM version 7.0.0 (clang-700.0.72)
         - os: osx
           osx_image: xcode7.1
-          compiler: gcc
-        - os: osx
-          osx_image: xcode7.1
-          compiler: clang
+          #Apple LLVM version 7.0.0 (clang-700.1.76)
         - os: osx
           osx_image: xcode7.2
-          compiler: gcc
-        - os: osx
-          osx_image: xcode7.2
-          compiler: clang
+          #Apple LLVM version 7.0.2 (clang-700.1.81)
         - os: osx
           osx_image: xcode7.3
-          compiler: gcc
-        - os: osx
-          osx_image: xcode7.3
-          compiler: clang
+          #Apple LLVM version 7.3.0 (clang-703.0.31)
 
 cache:
   apt: true