distrib: merge objcopy -Sg and strip commands

distrib: merge objcopy -Sg and strip commands

in the command "objcopy -Sg", the -g option (STRIP_DEBUG) overrides
the -S option (STRIP_ALL). so it is the same as "objcopy -g".

"strip" command without option is doing STRIP_ALL.

merge the both commands to "objcopy -S"

ok deraadt@ danj@