Warn for extern prototypes

[Sam Ravnborg <sam@ravnborg.org>]

Hi all.

Is it possible to get a warning when sparse encounter a
function prototype declared using "extern"?

So the following code:

extern void foo(void);
void bar(int x);

Would generate warnings because the declaration of foo()
uses extern.


I took a very short peek at evaluate.c - but decided to ask as maybe
there is already something that I overlooked or it is maybe trivial.

The rationale behind this is that at least in some areas of the kernel,
the use of "extern" for prototypes are no longer accepted.
A sparse warnings would be good to tell me all the cases I missed
in the conversion.

	Sam