add support for cmake build options (#809)

add support for cmake build options (#809)

* add initial support for cmake build options.

including basic library configuration.
Unlike our qmake build it generates and links with static libraries if
we are using our internally supplied copies.  The configuration options
are not as sophisticated as in our qmake build.  The configuration of
zlib will likely be acceptable as cmake provides support via findZLIB.
The configuration of shapelib and libusb-1.0 likely will likely need to
be enhanced.

* fix typo

* mimic qmake library searches.

too much energy went into verification with packagers that the
qmake options were sufficient for their needs.

* tweak library searches