Openspecfun provides AMOS and Faddeeva. AMOS (from Netlib) is a portable package
for Bessel Functions of a Complex Argument and Nonnegative Order; it contains
subroutines for computing Bessel functions and Airy functions. Faddeeva allows
computing the various error functions of arbitrary complex arguments (Faddeeva
function, error function, complementary error function, scaled complementary
error function, imaginary error function, and Dawson function); given these,
one can also easily compute Voigt functions, Fresnel integrals, and similar
related functions as well.