def _have(self, name=None):
if name is None:<EOL><INDENT>return (<EOL>(k, v) for k, v  in self.env.items()<EOL>if k.startswith('<STR_LIT>')<EOL>)<EOL><DEDENT>return self.env.get('<STR_LIT>' + self.env_key(name)) == True<EOL>
Check if a configure flag is set.

        If called without argument, it returns all HAVE_* items.

        Example:

            {% if have('netinet/ip.h') %}...{% endif %}