XDG screensaver: call waitpid immediately
XDG screensaver: call waitpid immediately

This requires one more thread :( but at least people won't report bug
about VLC leaving a defunct child process... Even though I doubt it
would have been a real problem.

vlc-mirror/vlc-2.1,krichter722/vlc,xkfz007/vlc,shyamalschandra/vlc,vlc-mirror/vlc-2.1,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.2,vlc-mirror/vlc,jomanmuk/vlc-2.2,krichter722/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,krichter722/vlc,shyamalschandra/vlc,vlc-mirror/vlc,krichter722/vlc,xkfz007/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc,jomanmuk/vlc-2.1,shyamalschandra/vlc,krichter722/vlc,jomanmuk/vlc-2.1,shyamalschandra/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,krichter722/vlc,vlc-mirror/vlc,shyamalschandra/vlc,vlc-mirror/vlc-2.1,vlc-mirror/vlc-2.1,xkfz007/vlc,krichter722/vlc,vlc-mirror/vlc,xkfz007/vlc,vlc-mirror/vlc-2.1,xkfz007/vlc,jomanmuk/vlc-2.1,shyamalschandra/vlc,jomanmuk/vlc-2.1,jomanmuk/vlc-2.2,vlc-mirror/vlc,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.1,xkfz007/vlc,jomanmuk/vlc-2.1,jomanmuk/vlc-2.2