Corrected ffi signature for approx1 & approx2 functions
Corrected ffi signature for approx1 & approx2 functions

9prady9/arrayfire-rust,9prady9/arrayfire-rust,9prady9/arrayfire-rust,9prady9/arrayfire-rust,botev/arrayfire-rust,jramapuram/arrayfire_rust,arrayfire/arrayfire-rust,tedsta/arrayfire-rust,pavanky/arrayfire-rust,arrayfire/arrayfire-rust,arrayfire/arrayfire-rust,arrayfire/arrayfire_rust