fixup! feat: Start using more than one thread while building

Jenkinsfile

@@ -81,7 +81,7 @@ pipeline {
         dir('gluon') {
           script {
             def nproc_str = sh "nproc"
-            def nproc = nproc_str as Integer
+            def nproc = nproc_str.toInteger()
             def nproc_plus_one = nproc+1
             sh "make -j${nproc_plus_one} GLUON_TARGET=${params.GLUON_TARGET}"
           }