topic: check availability of obsutil.getmarkers() for portability
Before this patch, topic extension causes unintentional failure with
Mercurial earlier than 4.3, because obsutil.getmarkers() has been
available since Mercurial 4.3 (tests for topic on mercurial-4.*
branches fail, too).
This breaks "minimumhgversion = '4.0'" declaration of topic extension.
This patch fixes this issue in a straightforward way for simplicity on
stable branch.
I'm planning to centralize such portability logic in topic extension
into topic/compat.py or so on default branch for efficiency at
runtime, like as evolve/compat.py.
exclude contrib
recursive-exclude contrib *
exclude hgext3rd/evolve/hack
recursive-exclude hgext3rd/evolve/hack *
exclude hgext3rd/evolve/legacy.py
exclude Makefile
exclude tests/test-drop.t
exclude tests/test-inhibit.t
exclude tests/test-oldconvert.t
include COPYING
include docs/figures/hgview-example.png
include docs/makefile
include docs/*.py
include docs/README
include docs/*.rst
include docs/static/*.svg
include docs/tutorials/*.t
include hgext3rd/__init__.py
include hgext3rd/evolve/*.py
include hgext3rd/topic/*.py
include MANIFEST.in
include README
include README-topic
include setup.py
include tests/*.py
include tests/*.sh
include tests/testlib/*.sh
include tests/*.t
prune debian
recursive-include docs/figures *.svg