Darwin's ld does not support --version-script, but it does support
-unexported_symbols_list, -force_symbols_not_weak_list, and
-force_symbols_weak_list that all take files as arguments.
Instead of expecting these to be added to the ldflags manually, add
properties for them so that the dependencies are handled appropriately.
Also sanity checks the darwin vs non-darwin usages early, so that the
error message is faster and more obvious.
Change-Id: I42526cc4367b6ea9adfdbb58753e12824e8c321c
93c2831af1