compiling dev_grads on Peregrine

[pgebraad]

On linux on Peregrine, to get things to compile, I needed to add the flag -fPIC:

gfortran -c -fPIC adBuffer.f
gcc -c -fPIC adStack.c

Although I am not sure what it means, maybe it is something to add to the readme.

[jaredthomas68]

As far as I understand it -fPIC makes the code independent of location (I think this has something to do with running on multiple nodes on a super computer). This option is also required for compiling on Marylou (BYU supercomputer).