[PATCH]: Use mpc_pow in the fortran frontend

[Kaveh R. Ghazi]

From: "Tobias Burnus" <burnus@net-b.de>

> PS: For those not following the MPC development, missing (C99/F2008)
> functions are mpc_acos, mpc_asin, mpc_atan, mpc_acosh, mpc_asinh,
> mpc_atanh. And MPFR misses (F2008) SCALED_ERFC. The implementation of
> all of those is planned; the inverse complex trigonometric/hyperbolic
> function will (hopefully) happen in the next few months.

The "arc" functions haven't been written yet in MPC, but as you say, they 
are planned (soon).

However what is the status of csinh/ccosh/ctanh and ctan in fortran?  These 
are currently available in MPC and could be added right now if the rest of 
the necessary infrastructure was put in place in the fortran frontend.  I 
believe C99 fallback implementations are included in 
libgfortran/intrinsics/c99_functions.c, so that shouldn't be a blocker.

        Thanks,
        --Kaveh