#223 Change prelink script to solve IOS 0.40 #import issue

src/ios/RNFetchBlob/RNFetchBlob.h

 //  Created by wkh237 on 2016/4/28.
 //
 
+// comment out this line if your RN project >= 0.40
 #define OLD_IMPORT
 
 #ifndef RNFetchBlob_h

src/scripts/prelink.js

     fs.writeFileSync(PACKAGE_GRADLE, main);
     console.log('adding OkHttp3 dependency to pre 0.28 project .. ok')
   }
+  else if (VERSION >= 0.40) {
+    console.log('Remove OLD_IMPORT for RN >= 0.40 project ..')
+    glob('**/RNFetchBlob.h',{}, function(err, files) {
+      if(Array.isArray(files)) {
+        var target = process.cwd() + '/' + files[0];
+        console.log('\033[92mPatching .. \033[97m' + target);
+        var data = fs.readFileSync(target);
+        fs.writeFileSync(target, String(data).replace(/^#define OLD_IMPORT$/, '// #define OLD_IMPORT'));
+        console.log('done.')
+      }
+    })
+  }
 
   console.log('Add Android permissions => ' + (addAndroidPermissions == "true"))