* Build and depend on ESMF.

* Remove spherepack_dp and use package spherepack-3.1

* udunits - ensure correct paths used.

* RANGS / GSHHS Ensure we can use external package


* Build failures:
 kfreebsd-* : depends on /dev/tty ? why?
 use 'tty' executable to discover a tty we can use

 hurd : missing dep on libgdal1-dev ? 

 s390x : missing dep on libhdfeos-dev ?  Segfault on testcase ...
