Ubuntu 20.04 Install Guest Additions for VirtualBox时有报错：
This system is currently not set up to build kernel modules.
Please install the gcc make perl packages from your distribution.
VirtualBox Guest Additions: Running kernel modules will not be replaced until the system is restarted.
解决方法：
# sudo apt install virtualbox-guest-utils virtualbox-guest-dkms
#sudo ./VBoxLinuxAdditions.run