Brings all flag definitions from the 'base' toolset into the 'toolset'
    toolset. Flag definitions whose conditions make use of properties in
    'prohibited-properties' are ignored. Don't confuse property and feature, for
    example <debug-symbols>on and <debug-symbols>off, so blocking one of them does
    not block the other one.

    The flag conditions are not altered at all, so if a condition includes a name,
    or version of a base toolset, it won't ever match the inheriting toolset. When
    such flag settings must be inherited, define a rule in base toolset module and
    call it as needed.

def inherit_flags(toolset, base, prohibited_properties = []):
    """Brings all flag definitions from the 'base' toolset into the 'toolset'
    toolset. Flag definitions whose conditions make use of properties in
    'prohibited-properties' are ignored. Don't confuse property and feature, for
    example <debug-symbols>on and <debug-symbols>off, so blocking one of them does
    not block the other one.

    The flag conditions are not altered at all, so if a condition includes a name,
    or version of a base toolset, it won't ever match the inheriting toolset. When
    such flag settings must be inherited, define a rule in base toolset module and
    call it as needed."""
    assert isinstance(toolset, basestring)
    assert isinstance(base, basestring)
    assert is_iterable_typed(prohibited_properties, basestring)
    for f in __module_flags.get(base, []):

        if not f.condition or b2.util.set.difference(f.condition, prohibited_properties):
            match = __re_first_group.match(f.rule)
            rule_ = None
            if match:
                rule_ = match.group(1)

            new_rule_or_module = ''

            if rule_:
                new_rule_or_module = toolset + '.' + rule_
            else:
                new_rule_or_module = toolset

            __add_flag (new_rule_or_module, f.variable_name, f.condition, f.values)