diff -up widelands-build20/CMakeLists.txt~ widelands-build20/CMakeLists.txt --- widelands-build20/CMakeLists.txt~ 2019-05-02 07:23:39.000000000 +0200 +++ widelands-build20/CMakeLists.txt 2019-05-13 15:21:05.368834756 +0200 @@ -167,7 +167,7 @@ else() message(FATAL_ERROR "Unknown CMAKE_BUILD_TYPE: ${CMAKE_BUILD_TYPE}") endif() -wl_add_flag(WL_GENERIC_CXX_FLAGS "-std=c++11") +wl_add_flag(WL_GENERIC_CXX_FLAGS "-std=gnu++11") if(OPTION_ASAN) message(STATUS "Using AddressSanitizer http://clang.llvm.org/docs/AddressSanitizer.html")