[vala/0.48] libvaladoc/girimporter: Fallback to "name" for callback

[Rico Tzschichholz <ricotz src gnome org>]

commit 5dd5db9d6cbc266052f6b58c8dbd9aecf25a7fe4
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Thu Aug 27 10:02:19 2020 +0200

    libvaladoc/girimporter: Fallback to "name" for callback
    
    This caused criticals like:
    
      valadoc_importer_gir_documentation_importer_attach_comment: assertion 'cname != NULL' failed

 libvaladoc/importer/girdocumentationimporter.vala | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/libvaladoc/importer/girdocumentationimporter.vala 
b/libvaladoc/importer/girdocumentationimporter.vala
index b528a178d..b94f64a96 100644
--- a/libvaladoc/importer/girdocumentationimporter.vala
+++ b/libvaladoc/importer/girdocumentationimporter.vala
@@ -655,6 +655,9 @@ public class Valadoc.Importer.GirDocumentationImporter : DocumentationImporter {
 
                case "callback":
                        c_identifier = reader.get_attribute ("c:type");
+                       if (c_identifier == null) {
+                               c_identifier = reader.get_attribute ("name");
+                       }
                        break;
 
                case "virtual-method":