- Switch to python3: add PYTHON=%{_bindir}/python3 to configure.
- Add: gtk-doc-open-docs-as-utf8.patch: Always open files using
utf-8. In python3, strings are differently represented
internally.

- Do not build as noarch:
/usr/share/gtk-doc/python/gtkdoc/config.py contains a full path
reference to $arch-pkg-config.

- Add gtk-doc-Generate-main-sgml.patch: Generate main sgml file by
waiting on mkdb. Fix first time parallel builds (bgo#786174).
- Following the above, add libtool BuildRequires and pass
autoreconf as the above patch touches the buildsystem.
- No longer pass --disable-scrollkeeper to configure, no longer
needed, nor recognized by configure.