ENH: For shared libraries when wrapping.

Instead of requiring the user to change the status of BUILD_SHARED_LIBS when
wrapping is ON, turn it ON for them and emit a warning.

Change-Id: Ic28fe787152b179416cef7c1d0977d41e13cc816
Merge topic 'WrappingShared'

3b7cda55 ENH: For shared libraries when wrapping.