gcc/gfortran can't find system library in latest Xcode/Mojave

[Christopher Jones]

Hi,

Just to add one detail to that below. Part of the problem is Xcode 11 even on maOS10.14 only supplies the 10.15 SDK. gcc when built gets the SDK baked into the default search paths it will use, and because you are  (I presume) using gcc binary install it is using the one built on the buildbot which is still using Xcode 10 and thus the 10.14 SDK. If you want to see what gcc is doing, try building with the -v option added….

So, additional solutions, if you want to avoid having to manually set the SDK root as you use gcc, are :-

1. revert back to Xcode 10 on mac OS 10.14, to match the buildbot.
2. rebuild gcc/libgcc from source yourself, so then the SDK will (I think…) match what you now have.

I would go with 1. as that will likely fix other residual issues with Xcode 11 on mac OS 10.14..

cheers Chris

3. I guess a third option is to update you OS to 10.15….

> On 10 Oct 2019, at 11:35 pm, Christopher Jones <jonesc at hep.phy.cam.ac.uk> wrote:
> 
> Hi,
> 
> Apple has been depreciating shipping the SDK  under /usr/include for some time now, and come Xcode11/macOS10.15 they are gone (with Xcode10 they where gone by default but you could add them back).
> 
> You need to specify the SDK root you need to use. See
> 
> https://www.mail-archive.com/macports-dev@lists.macports.org/msg06711.html <https://www.mail-archive.com/macports-dev@lists.macports.org/msg06711.html>
> 
> for a previous discussion.
> 
> Chris
> 
>> On 10 Oct 2019, at 11:20 pm, David Nicholls <david.nicholls at anu.edu.au <mailto:david.nicholls at anu.edu.au>> wrote:
>> 
>> Something Apple did in either the latest update to Mojave or the latest Xcode breaks gfortran's (8.3.0) ability to find the system library. I updated to the latest macports recently, too.  gfortran 8.3.0 that compiled code easily under previous versions of Mojave/Xcode/macports now throws an error:
>> 
>> M5118 error on build:
>> ld: library not found for -lSystem
>> collect2: error: ld returned 1 exit status
>> make[1]: *** [../lab/map51] Error 1
>> make: *** [build] Error 2 with gfortran 8.3.0
>> 
>> Does anyone know anything about this?
>> 
>> DN
>> 
>> David C Nicholls,
>> Research School of Astronomy & Astrophysics
>> Australian National University
>> 
>> 
> 

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