macOS Catalina: FAIL: t-powm

[Hans Åberg]

> On 15 Nov 2019, at 12:42, Torbjörn Granlund <tg at gmplib.org> wrote:
> 
> Apple has released a new version of Xcode.  It is said to fix some issue
> with UITextView, and as the update size is 8 GiB UITextView must be a
> very large function.
> 
> But hopefully they also managed to fix the C compiler to miscompile many
> of our functions.

No Xcode release will fix anything here, as I tried the official latest public clang, and Apple is using a much older one where they have carefully erased all version references to original clang so that users shall not know how old it in reality is.