Correct optimization from 3464f5e77f34; add a test.
If there are two (or more) heads that point to the same .hgtags
node, we can safely skip parsing the file in all but the last head.
(In 3464f5e77f34, we were parsing the file in the first head and
skipping all the others.)
include hg
recursive-include mercurial *.py
include hgweb.cgi hgwebdir.cgi
include hgeditor rewrite-log
include tests/README tests/*.py tests/test-*[a-z0-9] tests/*.out tests/*.bin
prune tests/*.err
include *.txt
include doc/README doc/Makefile doc/gendoc.py doc/*.txt doc/*.html doc/*.[0-9]
recursive-include templates *
recursive-include contrib *
recursive-include hgext *
include README
include CONTRIBUTORS
include COPYING
include Makefile
include MANIFEST.in
prune *.elc *.orig *.rej *~ *.o *.so *.pyc *.swp *.prof