CMakeLists.txt:add gnu option

Just wondering what would happen if I manually enabled gnu+11 extensions

(related:
069f36ee1f)

.travis.yml

@@ -14,6 +14,14 @@ matrix:
       env: Tr_Compiler_Version="7"
       # https://launchpad.net/~ubuntu-toolchain-r/+archive/ubuntu/test
       dist: trusty # broken compiler on 12.04
+    - os: linux
+      compiler: gcc
+      addons:
+          apt:
+            packages:
+            - libsdl2-dev
+      env: Tr_Compiler_Version="default"
+      dist: trusty
     - os: linux
       compiler: clang
       addons:

CMakeLists.txt

@@ -129,7 +129,7 @@ IF(CMAKE_COMPILER_IS_GNUCXX OR MINGW)
 
     # GCC specific Compiler Options
     ELSE()
-        ADD_DEFINITIONS("-frounding-math -fsignaling-nans")
+        ADD_DEFINITIONS("-std=gnu++11 -frounding-math -fsignaling-nans")
 
 #                IF(NOT MINGW)
 #                        set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS}   -rdynamic")