initial import of mpc 1.3.1. changes from 1.2.1 include:

New function: mpc_agm
New rounding modes "away from zero", indicated by the letter "A" and
corresponding to MPFR_RNDA on the designated real or imaginary part.
New experimental ball arithmetic.
New experimental function: mpc_eta_fund
Bug fixes:
- mpc_asin for asin(z) with small |Re(z)| and tiny |Im(z)|
- mpc_pow_fr: sign of zero part of result when the base has up to sign
the same real and imaginary part, and the exponent is an even positive
integer
- mpc_fma: the returned int value was incorrect in some cases
(indicating whether the rounded real/imaginary parts were
smaller/equal/greater than the exact values), but the computed complex
value was correct.
- Remove the unmaintained Makefile.vc; build files for Visual Studio are
maintained independently by Brian Gladman.

initial import of mpc 1.2.0. main changes are:

New functions:
mpc_sum
mpc_dot

Several functions are more robust with a reduced exponent range (for
example corresponding to IEEE 754 binary formats).