As a side effect of my Joy-in-Scheme effort, I put together a tiny
Chicken shim providing access to the procedures in the ISO C89 <math.h>
header that are not available in Chicken already. Because it's so short,
I'm attaching it here.
I'm not sure what the best way is to package this. Since its overhead
is near zero, I think the best final home for it is in either the library
or the extras unit (I'm not clear on what should go where with those two)
so that the procedures will routinely be available in the interpreter.
Alternatively it could be a standard unit or an egg. Failing that,
you can just (include "mathh.scm") into code to be compiled.