Updated Compile and install on macOS using macports (markdown)

Compile-and-install-on-macOS-using-macports.md

@@ -23,8 +23,8 @@ Install create-dmg:
     cd create-dmg
     chmod u+x create-dmg
     sudo cp create-dmg /opt/local/bin/
-    mkdir -p /opt/local/share/create-dmg
-    cp -r support /opt/local/share/create-dmg/
+    sudo mkdir -p /opt/local/share/create-dmg
+    sudo cp -r support /opt/local/share/create-dmg/
 
 Set environment variables: