gmp refuses to build c++ headers

[Hans Åberg]

> On 5 Aug 2020, at 23:57, John Perry <John.Perry at usm.edu> wrote:
> 
> However, deleting the directory, then re-extracting, seems to have fixed the problem. I’ve tried to reproduce it several times since, to no avail.

You can also build outside the source directory, say in a parallel directory called 'build' or something. Then move to that directory and call ../<source>/configure followed by 'make'. This is useful when trying several compilers, and is required for when building GCC.