In GLib 2.32, GStaticRecMutex has been deprecated in favor of GRecMutex. It occurs build error because of this build option - "-Werror=deprecated-declarations".
Created attachment 174106 [details] Patch
Like I said on IRC, the best way to go is to port the WebAudio backend to GStreamer 1.0. This patch won't build because GstTask in gst 0.10 requires a GStaticRecMutex.