For Perl 5.20.0, update patch to not introduce an empty if/then/else block,
which some shells prohibit.

Fixes build on Linux.
Update to 3.0.1:

This is a regularly-scheduled bugfix release.

    alias: change return code of bad definition to 255
    alias: fix loss of non-zero return code in command aliases
    alias: handle shlex error in command aliases
    bookmarks: properly align multi-byte characters
    bugzilla: support Bugzilla 4.4.3+ API login token authentication (issue4257)
    bundle2: fix bundle2 pulling all revs on empty pulls
    bundle2: fix configuration name mismatch
    changelog: ensure changelog._delaybuf is initialized
    color: don't fail on error messages when no curses (issue4237)
    exchange: propagate arguments to the _getbundleextrapart function
    localrepo: prevent leak of transaction object (issue4258)
    proxy: remove unneeded _set_hostport for compatibility with Python 2.7.7rc1
    setup.py, make: avoid problems with outdated, existing hgext/index.py*
    subrepo: avoid sanitizing ".hg/hgrc" in meta data area for non-hg subrepos
    subrepo: invoke "_sanitize()" also after "git merge --ff"
    subrepo: make "_sanitize()" take absolute path to the root of subrepo
    subrepo: make "_sanitize()" work
    subrepo: normalize path in the specific way for problematic encodings
    templates: fix ifcontains against sets with length > 1 (issue4259)
    win32: backout 1a9ebc83a74c
Updated devel/py-mercurial to 3.0.1
This package builds using cmake these days, so CONFIGURE_ARGS isn't useful.
Port the intended flags to cmake arguments.

Fixes the build in obscure circumstances where doxygen is installed, but
some documentation python build-time requirements happen to be missing.