Automagic Mac SDK location/version detection
Automagic Mac SDK location/version detection

The intent is that with no SDK related configure options, an optimal
SDK and 10.4 as minimum OS will be chosen. A warning is displayed if
building a LO that will not (either definitely not, or probably not)
run on 10.4, as 10.4 continues to be our minimum supported OS.

Change-Id: I6683aa43362881a135637e878bfc469591ab9d20

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core