Changelog

Rewrite the configure script using autoconf and test it on all the platforms supported by rhub.
Update the internal PROJ copy to 8.1.0.
Rewrite tests to make sure the C API can be linked to and don’t skip them on any platform.
Test using a wrapper package that uses most of the exported functions (see https://github.com/paleolimbot/rlibproj)
Update the README with examples of how to make use of this package (optionally using Rcpp or cpp11 as a helper)
Correctly declare system requirements.
Update configuration options to be more robust across environments.

Fixed linking to libtiff on Solaris and Ubuntu 20.04.
Update to PROJ 7.2.0 and SQLite 3.34.0.
Added ca_bundle_path to libproj_configuration().
libproj_configure() now properly checks for errors when calling the underlying PROJ functions.

libproj 8.1.0-1 2021-10-05