buildroot

readline: fix stripping on target

Libraries got installed read only, so strip failed.

[Peter: simplify chmod logic]
Signed-off-by: Carlos Santos <casantos@datacom.ind.br>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>