Minor fix to installation error

[jpdeleon]

I am using Ubuntu:
$ uname -a
Linux dl 4.13.0-36-generic #40~16.04.1-Ubuntu SMP Fri Feb 16 23:25:58 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

When I tried to install planetplanet:
$pip install -U --no-deps planetplanet

I get the following error:
#include <gsl/gsl_poly.h>
^
compilation terminated.
error: command 'gcc' failed with exit status 1

I have gcc already installed:
$ gcc --version
gcc (GCC) 4.8.5

So I fixed this issue by installing the GSL library:
$ apt-get install gsl-bin libgsl0-dev

I am not sure if this is useful but others might find the same issue in case.

[PS-OnGit]

Had the same error but this fixed it!
using Python3.6.9 and Ubuntu 18.04

Thanks!

[marcoeangeli]

Can confirm, this was also an issue on Arch Linux. Fixed it by running
pacman -S gsl