fallback : ['gstreamer', 'gst_dep'])
gstbase_dep = dependency('gstreamer-base-1.0', version : gst_req,
fallback : ['gstreamer', 'gst_base_dep'])
fallback : ['gstreamer', 'gst_dep'])
gstbase_dep = dependency('gstreamer-base-1.0', version : gst_req,
fallback : ['gstreamer', 'gst_base_dep'])