branches: 1.1.1.1.2; 1.1.1.1.8;
initial import of MPRF 3.0.1.

The MPFR library is a C library for multiple-precision floating-point
computations with exact rounding (also called correct rounding). It is
based on the GMP multiple-precision library and should replace the MPF
class in further releases of GMP.

GCC >= 4.2 requires MPFR.