fix node 16.x build error

binding.gyp

@@ -28,7 +28,7 @@
         }
       },
       'xcode_settings': {
-        'CLANG_CXX_LANGUAGE_STANDARD': 'c++11',
+        'CLANG_CXX_LANGUAGE_STANDARD': 'c++14',
         'CLANG_CXX_LIBRARY': 'libc++',
         'OTHER_LDFLAGS': [],
         'GCC_ENABLE_CPP_EXCEPTIONS': 'NO',
@@ -81,7 +81,7 @@
         }],
         ['OS!="win"', {
           'cflags_cc+': [
-            '-std=c++0x'
+            '-std=c++14'
           ]
         }]
       ]