wip/mpc 1.3.1 NetBSD

MPC is a complex floating-point library with exact rounding. It is based on the GNU MPFR floating-point library, which is itself based on the GNU MP library.

This is a C library for the arithmetic of complex numbers with arbitrarily high precision and correct rounding of the result. It extends the principles of the IEEE-754 standard for fixed precision real floating point numbers to complex numbers, providing well-defined semantics for every operation. At the same time, speed of operation at high precision is a major design goal.