[Bug other/102664] contrib/gcc-git-customization.sh uses echo -n, which isn't portable

[egallager at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102664

--- Comment #27 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #26)
> Does it work on macOS now?

Yes, thanks! All that remains now is the original `echo -n` problem...
Actually, let me test to see if the autolinking works with the output:

$ git gcc-descr 716bb02b
r12-94-g716bb02b40ecef
$

...ok, good!