old_contents: {
   "targets": [
     {
       "target_name": "addon",
       "sources": [
         "src/addon.cc",
         "src/object.cc",
         "src/async.cc",
         "src/engine.cc",
         "src/results.cc"
       ],
       "cflags!": [ "-fno-exceptions" ],
       "cflags_cc!": [ "-fno-exceptions" ],
       "include_dirs": ["<!@(node -p \"require('node-addon-api').include\")"],
       "dependencies": ["<!(node -p \"require('node-addon-api').gyp\")"],
       "defines": [ "NAPI_CPP_EXCEPTIONS", "NODE_ADDON_API_DISABLE_DEPRECATED" ],
       "conditions": [
         ["OS==\"win\"", {
           "msvs_settings": {
             "VCCLCompilerTool": {
               "ExceptionHandling": 1
             }
           }
         }],
         ["OS==\"mac\"", {
           "xcode_settings": {
             "CLANG_CXX_LIBRARY": "libc++",
             "GCC_ENABLE_CPP_EXCEPTIONS": "YES",
             "MACOSX_DEPLOYMENT_TARGET": "10.7",
             "__GCC_ENABLE_CPP_RTTI" : "YES"
           }
         }]
       ]
     }
   ]
  }
new_contents: {
   "targets": [
     {
       "target_name": "addon",
       "sources": [
         "src/addon.cc",
         "src/object.cc",
         "src/async.cc",
         "src/engine.cc",
         "src/results.cc"
       ],
       "cflags": [ "-Werror", "-Wall", "-Wextra", "-Wpedantic", "-Wunused-parameter" ],
       "cflags_cc": [ "-Werror", "-Wall", "-Wextra", "-Wpedantic", "-Wunused-parameter" ],
       "cflags!": [ "-fno-exceptions" ],
       "cflags_cc!": [ "-fno-exceptions" ],
       "include_dirs": ["<!@(node -p \"require('node-addon-api').include\")"],
       "dependencies": ["<!(node -p \"require('node-addon-api').gyp\")"],
       "defines": [ "NAPI_CPP_EXCEPTIONS", "NODE_ADDON_API_DISABLE_DEPRECATED" ],
       "conditions": [
         ["OS==\"win\"", {
           "msvs_settings": {
             "VCCLCompilerTool": {
               "ExceptionHandling": 1
             }
           }
         }],
         ["OS==\"mac\"", {
           "xcode_settings": {
             "CLANG_CXX_LIBRARY": "libc++",
             "GCC_ENABLE_CPP_EXCEPTIONS": "YES",
             "MACOSX_DEPLOYMENT_TARGET": "10.7",
             "__GCC_ENABLE_CPP_RTTI" : "YES"
           }
         }]
       ]
     }
   ]
  }
subject: add flags