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

[egallager at gcc dot gnu.org]

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

--- Comment #19 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Martin Liška from comment #10)
> > I still get "expr: syntax error" when trying to do `git gcc-descr 716bb02b`
> > after re-running `sh ./contrib/gcc-git-customization.sh`
> 
> Ok, so can you please run:
> 
> $ bash -x ./contrib/git-descr.sh 716bb02b
> 

Ok, I've updated; output of that is now:

$ bash -x ./contrib/git-descr.sh 716bb02b
+ short=no
+ long=no
+ c=master
+ for arg in '"$@"'
+ case "$arg" in
+ c=716bb02b
+ test xno = xyes
+ test xno = xyes
++ git describe --all --abbrev=14 --match 'basepoints/gcc-[0-9]*' 716bb02b
++ sed -n 's,^\(tags/\)\?basepoints/gcc-,r,p'
+ r=
+ expr no : 'r[0-9]\+$'
+ test -n
++ git config --get gcc-config.upstream
+ o=origin
++ echo
++ sed -n 's,^r\([0-9]\+\)-[0-9]\+\(-g[0-9a-f]\+\)\?$,\1,p'
+ rr=
+ git rev-parse --verify --quiet origin/releases/gcc-
+ m=master
+ git merge-base --is-ancestor 716bb02b origin/master
+ echo
$

> What OS do you use?

macOS 11.6.4 (Big Sur)