Environmental exports to use conda installed perl.

def get_perl_exports(tmpdir=None):
    """Environmental exports to use conda installed perl.
    """
    perl_path = os.path.dirname(perl_cmd())
    out = "unset PERL5LIB && export PATH=%s:\"$PATH\"" % (perl_path)
    if tmpdir:
        out += " && export TMPDIR=%s" % (tmpdir)
    return out