bitbake: bitbake: Force -S option to take a parameter

There is no easy way to make this change. We really need parameters for the -S
(dump signatures) handling code. Such a parameter can then be used within the
codebase to handle the signatures in different ways.

For now, "none" is the recommended default and "printdiff" will execute the
new (and more expensive) comparison algorithms.

(Bitbake rev: b9873588696507dfb6aade6821f6f75cb9a19e0a)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/cookerdata.py

@@ -124,7 +124,7 @@ class CookerConfiguration(object):
         self.profile = False
         self.nosetscene = False
         self.invalidate_stamp = False
-        self.dump_signatures = False
+        self.dump_signatures = []
         self.dry_run = False
         self.tracking = False
         self.interface = []