It's only needed for the taglib plugin which is optional.
taglib_dep = dependency('taglib', version : '>= 1.5', required : false)
-if taglib_dep.found() and add_languages('cpp')
+if taglib_dep.found() and add_languages('cpp', required : false)
gsttaglib = library('gsttaglib',
taglib_sources,
c_args : gst_plugins_good_args + ['-DGST_USE_UNSTABLE_API'],
-project('gst-plugins-good', 'c', 'cpp',
+project('gst-plugins-good', 'c',
version : '1.13.0.1',
meson_version : '>= 0.36.0',
default_options : [ 'warning_level=1',