glib-2.0: Use async scope for GThreadFunc
glib-2.0: Use async scope for GThreadFunc

Fixes bug 680931.

flobrosch/vala-fixes,frida/vala,playya/vala,Distrotech/vala,spidermonkdust/vala,flobrosch/vala-fixes,severinh/vala,playya/vala,flobrosch/vala-fixes,playya/vala,GNOME/vala,severinh/vala,frida/vala,frida/vala,rvu95/vala,Distrotech/vala,GNOME/vala,Distrotech/vala,rvu95/vala,GNOME/vala,frida/vala,xdave/pvala,GNOME/vala,rvu95/vala,severinh/vala,spidermonkdust/vala,spidermonkdust/vala,frida/vala