[docs] build command change of node.js in NW: define building_nw=1

rogerwang · rogerwang · commit 4e7b52901e9f · 2017-11-14T10:43:54.000+08:00
Ref nwjs#5971
diff --git a/docs/For Developers/Building NW.js.md b/docs/For Developers/Building NW.js.md
@@ -88,12 +88,12 @@ See the upstream documentation for the mapping between GN and GYP flags: https:/
 
 ```bash
 cd src
-GYP_CHROMIUM_NO_ACTION=0 ./build/gyp_chromium -I third_party/node-nw/common.gypi third_party/node-nw/node.gyp
+GYP_CHROMIUM_NO_ACTION=0 ./build/gyp_chromium -I third_party/node-nw/common.gypi -D building_nw=1 third_party/node-nw/node.gyp
 ```
 
 or use the following if you're doing a component build:
 ```bash
-./build/gyp_chromium -D component=shared_library -I third_party/node-nw/common.gypi third_party/node-nw/node.gyp
+./build/gyp_chromium -D component=shared_library -I third_party/node-nw/common.gypi -D building_nw=1 third_party/node-nw/node.gyp
 ```
 To change the build configuration for Node, you need to setup the GYP_DEFINES environment variable:
 
