Need to check for static targets before adding abi visibility flags.

If shared libraries are getting built there may still be some
libraries that are set to be built statically. I added in a check
to see if the target was a static library before adding in extra
compile flags.

Change-Id: I0c3de83964faef78a421824e07f0180742848b9f
Merge topic 'fix_visibility_for_static_targets' into master

2e8ba2b7 Need to check for static targets before adding abi visibility flags.