Documentation for build dependencies

[systemed]

Thanks for this project!

The Pod requires GNU build dependencies to install, namely aclocal, autoheader and libtoolize:

Installing crs-ios (1.0.4)
Installing proj-ios (1.0.4)
Installing proj4-ios (4.9.3)
[!] /bin/bash -c 
set -e
./autogen.sh
./configure

Running aclocal

  Something went wrong, giving up!

./autogen.sh: line 29: aclocal: command not found

I installed them using Homebrew (suitably neutered to prevent it breaking stuff as per):

HOMEBREW_NO_AUTO_UPDATE=1 brew install --build-from-source automake libtool

and the Pod then built successfully. It would be good to mention these dependencies in the README.

[bosborn]

This was specified in our GeoPackage library which depends on this library. I copied that dialogue to this library and Simple Features Projection.