Changing default cxx_stdlib to libc++

[db]

On 10 Mar 2018, at 00:09, Joshua Root <jmr at macports.org> wrote:
> On 2018-3-10 08:43 , db wrote:
>> 
>> If I build base and ports from source, will buildfromsource be changed unilaterally by MP or would it need user intervention? I also have certain versions of gcc and llvm locally to avoid rebuilding after minor versions and revbumps.
> We're not going to modify your macports.conf.

How will I know about the lib change and the availability of binaries? Besides rebuilding from source from time to time, I only do port sync.