Installation is non-trivial if you install from __source_ because of
the SystemRequirements (listed in
./DESCRIPTION):
MPFR, the “Multiple Precision Floating-Point Reliably” library
which is Free/Libre Software, available under the LGPL license. MPFR Website
GNU Multiple Precision arithmetic library (GMP)
Obtain that from GMP Website or from your operating system vendor / package system:
+ Under _Debian_, _Ubuntu_ (and other Debian derivative) Linux distributions,
  it is sufficient (for *both* libraries) to simply do  sudo apt-get install libmpfr-dev+ In Fedora, Redhat, CentOS, opensuse, etc, you get these via  sudo dnf install mpfr-devel@article{FouLHLPZ-2007,
 author = {Laurent Fousse and Guillaume Hanrot and Vincent Lef\`{e}vre and
       Patrick P\'{e}lissier and Paul Zimmermann},
 title = {MPFR: A multiple-precision binary floating-point library with
          correct rounding},
 year = {2007},
 journal = {ACM Trans. Math. Softw.},
 volume = {33},
 number = {2},
 issn = {0098-3500},
 pages = {13},
 doi = {http://doi.acm.org/10.1145/1236463.1236468},
 publisher = {ACM},
 address = {New York, NY, USA},
}