Re: Emacs 28.1 doesn't compile on Mac OS 10.7.5

[Werner LEMBERG]

>> Looks like directory configuration issues that I know nothing about.

I've now submitted a first PR for MacPorts

  https://github.com/macports/macports-ports/pull/14594

so that it can eventually be used by admins for triggering builds on
older macOS versions (this isn't done automatically AFAIK).

Lo and behold, it also reports problems with current git on recent
macOS versions (10.15 and 11.0) :-)

```
sysdep.c:4147:41: error: implicit declaration of function
  'timeval_to_timespec' is invalid in C99
  [-Werror,-Wimplicit-function-declaration]
struct timespec t = timespec_add (timeval_to_timespec (rusage->ru_utime),
```

This is from the logfiles for subports 'emacs-devel' and
'emacs-app-devel' based on emacs commit 8259e368001a6e3; the above PR
also contains links to the full logs if needed.


    Werner