在启动VirtualBox里的虚拟机的时候，弹出个如下报错：
No audio device could be opened.Select the NULL audio backend with the consequence that no sound is audible.
Error ID: HostAudioNotResponding
Severity: Warning
启动之后就是虚拟机里没有声音，原来是 media-libs/libsdl 造成的，解决办法就是在/etc/portage/package.mask里把高于1.2.14屏蔽掉，然后重新emerge
No audio device could be opened.Select the NULL audio backend with the consequence that no sound is audible.
Error ID: HostAudioNotResponding
Severity: Warning
启动之后就是虚拟机里没有声音，原来是 media-libs/libsdl 造成的，解决办法就是在/etc/portage/package.mask里把高于1.2.14屏蔽掉，然后重新emerge
