🚀 go-pugleaf

    What I would really like to do, is turn off builtin functions, and the
    builtin function prototypes.

This is the wrong approach, for a basic philosophical reason.

You have found a feature which, in a particular case, fails to work.
To think that the solution is to turn off the feature is to assume
that it can *never* work.

But it is absurd to assume that.  We don't know why it does not work.
It may be failing for a trivial reason.  It is silly to give up on the
feature without first checking the possibility that it can easily be
fixed.

I can't tell you what to do.  Those of you who wish to give up on a
feature can do so.  But for those of you who are interested in what I
have to say, I urge you to take a constructive approach and help get
things fixed.

See the Bugs chapter of the GCC manual for a general guide to how to do this.

In the case of a type conflict with a built-in function, the main
useful thing for you to do is to find the declaration that conflicts
and tell us precisely what data types the conflicting declaration
uses.  Most importantly, find out what size_t is in the system headers.