Raise glib dependency to 2.38

Needed for G_DEFINE_TYPE_WITH_PRIVATE
EogWindow: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogTransform: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogThumbView: Convert to G_DEFINE_TYPE_WITH_PRIVATE

Use G_ADD_PRIVATE directly in this case.
EogSidebar: Use G_DEFINE_TYPE_WITH_PRIVATE
EogScrollView: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogURIConverter: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogThumbNav: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogStatusbar: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogPropertiesDialog: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogPrintPreview: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogPrintImageSetup: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogPreferencesDialog: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogPluginEngine: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogMetadataSidebar: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogMetadataReader: Convert to G_DEFINE_TYPE_WITH_PRIVATE

Use G_ADD_PRIVATE for this due to G_DEFINE_TYPE_WITH_CODE
EogListStore: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogImage: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogFileChooser: Convert to G_DEFINE_TYPE_WITH_PRIVATE
EogExifDetails: Convert to G_DEFINE_TYPE_WITH_PRIVATE