[gtk-doc] mkhtml2: skip sections without 'id' atts for refentry nav

[Stefan Sauer <stefkost src gnome org>]

commit 0530af38534d990e3b8a433fe6c7acc007d74be7
Author: Stefan Sauer <ensonic users sf net>
Date:   Fri Mar 30 21:10:28 2018 +0200

    mkhtml2: skip sections without 'id' atts for refentry nav
    
    It only makes sense to link to them if they have an id.

 gtkdoc/mkhtml2.py |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtkdoc/mkhtml2.py b/gtkdoc/mkhtml2.py
index a6d4b43..7653d9b 100644
--- a/gtkdoc/mkhtml2.py
+++ b/gtkdoc/mkhtml2.py
@@ -876,6 +876,9 @@ def generate_refentry_nav(ctx, refsect1s, result):
         # don't list TOC sections (role="xxx_proto")
         if s.attrib.get('role', '').endswith("_proto"):
             continue
+        # skip section without 'id' attrs
+        if 'id' not in s.attrib:
+            continue
 
         title = xml_get_title(s)
         result.append("""