Support parameter -j to set jobs for make

nvm.sh

@@ -1232,6 +1232,7 @@ nvm_install_node_source() {
     MAKE_CXX="CXX=c++"
   fi
 
+  if [ -z "$MAKE_JOBS" ]; then
     if [ "_$NVM_OS" = "_linux" ]; then
       CPU_THREADS="$(grep -c 'core id' /proc/cpuinfo)"
     elif [ "_$NVM_OS" = "_freebsd" ] || [ "_$NVM_OS" = "_darwin" ]; then
@@ -1255,6 +1256,7 @@ nvm_install_node_source() {
         echo "Number of CPU thread(s) less or equal to 2 will have only one job a time for 'make'"
       fi
     fi
+  fi
   local tmpdir
   tmpdir="$NVM_DIR/src"
   local tmptarball
@@ -1579,6 +1581,21 @@ nvm() {
       if [ "_$1" = "_-s" ]; then
         nobinary=1
         shift
+        if [ "_$1" = "_-j" ]; then
+          shift
+          local CPU_THREAD_VALID
+          CPU_THREAD_VALID=$(nvm_is_natural_num $1)
+          if [ "$CPU_THREAD_VALID" = "true" ]; then
+            MAKE_JOBS=$1
+            echo "Set number of jobs to $MAKE_JOBS for 'make' utility"
+          else
+            unset MAKE_JOBS
+            echo >&2 "$1 is invalid for CPU threads, should be a natural number"
+          fi
+          shift
+        else
+          unset MAKE_JOBS
+        fi
       fi
 
       provided_version="$1"