How to get AC_DEFINE to generate a macro, e.g., #define incr(x) ((x)+1) ?

[Fred Proctor]

How can one get AC_DEFINE to define a variable with an argument list? I 
want to do something like this:

AC_DEFINE(incr(x),((x)+1),"increment")

The parens in the value part, ((x)+1), go across OK. The parens in the 
variable part, incr(x), are killing me.

--Fred