Thanks, I didn't know c99 had standardized that.

However.. I'm still skeptical whether a macro can figure out how deep
the variadic call should be for a given point in the mib.

If a macro can do that, then we shouldn't need to expose the variadic
functions as part of the API. The API could instead wrap the variadic
functions with suitable fixed-length versions for node/int/struct, a
la FreeBSD's SYSCTL_{NODE,INT,STRUCT} macros.

That's my real gripe. Maybe Andrew can clarify why the API has to be
variadic.