build: do gst-style git versioning, so AS_NANO works properly
build: do gst-style git versioning, so AS_NANO works properly

https://bugzilla.gnome.org/show_bug.cgi?id=690364

freedesktop-unofficial-mirror/gstreamer__attic__gst-openmax,freedesktop-unofficial-mirror/gstreamer__attic__gst-openmax