Build script: Replace `exec` with `spawn`

dist/build-package.js

@@ -1,15 +1,12 @@
-var exec = require('child_process').exec;
-function puts(error, stdout, stderr) { console.log(stdout) }
-
+var spawn = require('child_process').spawn;
 var os = require('os');
-//control OS
-//then run command depengin on the OS
 
-if (os.type() === 'Linux') 
-   exec("dist/package.sh", puts); 
-else if (os.type() === 'Darwin') 
-   exec("dist/package.sh", puts); 
-else if (os.type() === 'Windows_NT') 
-   exec("powershell dist/package.sh", puts);
-else
-   throw new Error("Unsupported OS found: " + os.type());
+if (os.type() === 'Linux') {
+   spawn('bash', ['dist/package.sh'], {stdio: 'inherit'});
+} else if (os.type() === 'Darwin') {
+   spawn('bash', ['dist/package.sh'], {stdio: 'inherit'});
+} else if (os.type() === 'Windows_NT') {
+   spawn('powershell', ['dist/package.sh'], {stdio: 'inherit'});
+} else {
+   throw new Error("Unsupported OS found: " + os.type());
+}