c/7425: deprecated attribute doesn't merge with multiple declarations

[Falk Hueffner]

This boils down to

void func(void);
void func(void) __attribute__((deprecated));

void f(void) {
    func();
}

I'm not sure what is supposed to happen with multiple declarations
with conflicting attributes, I cannot find anything in the manual
about this. Do we really want to "merge" them? What should happen if
they conflict? Other options seem to be "choose any" and "choose the
later". Current behaviour seems to be "choose any".

-- 
	Falk