autoreconf in repo-usage.html

[Marc Glisse]

Hello,

in http://gmplib.org/devel/repo-usage.html , we say:

"Do not use autoreconf; it will overwrite config.guess which in turn will 
cause any builds to be awful."

However, .bootstrap runs autoreconf... Maybe we should be more specific 
and say:

"Do not use autoreconf -f; it will..."

?

-- 
Marc Glisse