Address comments

Author: minggangw

lib/native_loader.js

@@ -106,7 +106,7 @@ function loadNativeAddon() {
       debug('Running forced node-gyp rebuild...');
       execSync('npm run rebuild', {
         stdio: 'inherit',
-        cwd: __dirname + '/..',
+        cwd: path.join(__dirname, '..'),
         timeout: 300000, // 5 minute timeout
       });
 
@@ -170,7 +170,7 @@ function loadNativeAddon() {
       debug('Running node-gyp rebuild...');
       execSync('npm run rebuild', {
         stdio: 'inherit',
-        cwd: __dirname + '/..',
+        cwd: path.join(__dirname, '..'),
         timeout: 300000, // 5 minute timeout
       });