How to add functions?

I'm not sure what you are doing with the local version of `@ccall`.
I'd like to add some functions via PR. I know how to do it this way:
```
const LibQM = dlopen(find_library(Quadmath.libquadmath))

Base.rem(x::Float128,y::Float128) =
ccall(dlsym(LibQM, :fmodq), Float128, (Float128, Float128), x, y)
```
How is this best done in keeping with the structure of the package?