Building against the local /System can cause build issues when for example
the headers have not been updated to reflect the system version. The system
headers are updated as part of installing the command line tools from within
Xcode, not as part of the system update process, so we might think we are
on 10.8, but the system headers will not reflect that, and we get build
breaks. It's preferable to always build against an SDK, so that we have
a known state for the OS X libraries and headers.
We choose the latests SDK by default, as recommended by Apple.
Change-Id: I79028217ff3a9cbe45aa4cb05ed6dd90388dee50
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>
c3a5681225