travis: enable strict C++11 compilation

.travis.yml

@@ -40,6 +40,7 @@ before_install:
 
     - if [ "$BUILD" = 3 ]; then export ALTERNATE_CONFIGURATION=true; fi
     - if [ "$BUILD" = 4 ]; then export CXX11=true; fi
+    - if [ "$BUILD" = 4 ]; then export EXTRA_FLAGS_RELEASE="-O0 -Wno-literal-suffix -Wno-deprecated-declarations"
     - if [ "$BUILD" = 4 ]; then export CPP_TESTS=false; fi
     - if [ "$BUILD" = 5 ]; then export NLS=true; fi
     - if [ "$BUILD" = 5 ]; then export TARGETS="translations"; fi
@@ -53,7 +54,7 @@ before_install:
     - if [ "$CXX" = "g++" ]; then export WML_TESTS=false; fi
     - if [ "$CXX" = "g++" ]; then export PLAY_TEST=false; fi
     - if [ "$CXX" = "g++" ]; then export CHECK_UTF8=false; fi
-    - if [ "$CXX11" = true ]; then export STRICT_COMPILATION=false; fi
+#    - if [ "$CXX11" = true ]; then export STRICT_COMPILATION=false; fi
 
 install:
     - sudo add-apt-repository -y "deb http://archive.ubuntu.com/ubuntu/ saucy main universe"

src/SDL_SavePNG/savepng.cpp

@@ -5,26 +5,8 @@
  * http://www.libpng.org/pub/png/src/libpng-LICENSE.txt
  */
 #include <SDL.h>
-
-#ifdef __GNUC__
-#if __GNUC__ > 4 || __GNUC__== 4 && __GNUC_MINOR__ >= 9
-#define HAVE_GCC_4_9
-#endif
-#endif
-
-#ifdef HAVE_GCC_4_9
-#pragma GCC diagnostic push
-#ifndef __clang__
-#pragma GCC diagnostic ignored "-Wliteral-suffix" //GCC 4.9 with C++11 gives a warning about this in libpng header
-#endif
-#endif
-
 #include <png.h>
 
-#ifdef HAVE_GCC_4_9
-#pragma GCC diagnostic pop
-#endif
-
 #include "savepng.h"
 
 #define SAVEPNG_SUCCESS 0