geographiclib: files missing from install

[crmoore (Chris Moore)]

The following files are not installed by the port, but are by the upstream cmake build system.

$prefix/lib/cmake/GeographicLib/geographiclib-config-version.cmake $prefix/lib/cmake/GeographicLib/geographiclib-config.cmake $prefix/lib/cmake/GeographicLib/geographiclib-targets-release.cmake $prefix/lib/cmake/GeographicLib/geographiclib-targets.cmake

The upstream provides several build systems (autotools and cmake among others), and documents cmake as preferred.

Not sure what the macports policy is on how to choose which one to use, but the installed fileset is slightly different with each.