Mac OS X make doesn't recognize the private modifier

I'm trying to write a make rule and want to suppress inheritance of a variable as described in make manual. I go like that:

$(my_lib): private LFLAGS +=开发者_Python百科 \
    whatever

When I try to use it, make complains it cannot find a rule to make the private target. Is this a problem/deficiency in Mac OS X make (GNU Make v3.81) or am I missing something in my syntax? (I tried it with plain assignment = instead of += with the same result.)

The private modifier was introduced in GNU make 3.82. You are using 3.81, which is why you see that error.