Dealing with Xcode 9 + macOS <= 10.12 and missing functions

[Leonardo Brondani Schenkel]

On 2017-09-29 10:23, Joshua Root wrote:
> On 2017-9-29 18:14 , Leonardo Brondani Schenkel wrote:
>> This seems to be an issue in XCode 9 to me, since I believe that when 
>> setting the deployment target to 10.12 or earlier it should not be 
>> exposing symbols that are not available at runtime.
> 
> It is working correctly as far as it goes; autoconf just doesn't solve 
> the entire problem. Symbols that are not available on all the OS 
> versions being targeted must be checked for at runtime before use. That 
> way a single binary can use newer APIs when they are available but still 
> run on older OS releases.

Fair enough. I think I don't fully understand the role of "deployment 
target": to me it was the *maximum* version I want to be able to link 
against, but apparently it is the opposite.

However, the motivation for my the original post was more to talk about 
if it makes sense to have something done on MacPorts level to mitigate 
this issue or just deal with it on a port-by-port basis. Just to be 
clear: I'm not advocating one or the other — I'm just curious about what 
the lists thinks.

// Leonardo.