* Add deployment targets for osx
* Fix bundle path to make spec tests work
On iOS, resources are directly within the bundle so the bundlePath and
the resourcePath are the same.
On macOS, resources are in a Contents/Resources subfolder so enumerating
from bundlePath causes us to look for names like
Contents/Resources/offline_spec_test, which doesn't work.
* Fix documentation warnings that show up under the macOS build
This involves:
- building c++ libprotobuf (rather than just the obj-c version).
- adding c++ libprotobuf, c++ built protos (previously created) to the
*test suite* only (not to the main build).
- modifying existing nanopb CFLAGS to match those that are indirectly
pulled in.
Paul Beusterien