Added C++ standard as a compiler flag, which is apparently needed by compilers on macOS

meson.build

@@ -1,5 +1,6 @@
 project('Pong', ['cpp', 'c'], version: '0.1')
 add_global_arguments('-g', '-Wall', '-pedantic', '-Wno-unused-function', '-Wno-narrowing', language : ['cpp', 'c'])
+add_global_arguments('-std=c++11', language: ['cpp'])
 compiler = meson.get_compiler('cpp')
 cmake = import('cmake')
 
@@ -32,7 +33,7 @@ if build_machine.system() == 'windows'
 
 endif
 
-executable('pong', 
+executable('pong',
 	'main.cpp', 'sock.cpp','paddle.cpp', 'ball.cpp', 'numeric_base.cpp', 'connect_code.cpp', 'server.cpp', 'client.cpp', 'check_input.cpp', 'raygui_helpers.cpp',
 	'serialization.c', 'timer.c', 'easysock.c',
 	dependencies: [raylib, ws2_dep, winmm]