minikconf: do not include variables from MINIKCONF_ARGS in config-all-devices.mak

When minikconf writes config-devices.mak, it includes all variables including
those from MINIKCONF_ARGS.  This causes values from config-host.mak to "stick" to
the ones used in generating config-devices.mak, because config-devices.mak is
included after config-host.mak.  Avoid this by omitting assignments coming
from the command line in the output of minikconf.

Reported-by: Christophe de Dinechin <dinechin@redhat.com>
Reviewed-by: Christophe de Dinechin <dinechin@redhat.com>
Tested-by: Christophe de Dinechin <dinechin@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

scripts/minikconf.py

@@ -688,11 +688,13 @@ def scan_token(self):
 
     data = KconfigData(mode)
     parser = KconfigParser(data)
+    external_vars = set()
     for arg in argv[3:]:
         m = re.match(r'^(CONFIG_[A-Z0-9_]+)=([yn]?)$', arg)
         if m is not None:
             name, value = m.groups()
             parser.do_assignment(name, value == 'y')
+            external_vars.add(name[7:])
         else:
             fp = open(arg, 'r')
             parser.parse_file(fp)
@@ -700,7 +702,8 @@ def scan_token(self):
 
     config = data.compute_config()
     for key in sorted(config.keys()):
-        print ('CONFIG_%s=%s' % (key, ('y' if config[key] else 'n')))
+        if key not in external_vars:
+            print ('CONFIG_%s=%s' % (key, ('y' if config[key] else 'n')))
 
     deps = open(argv[2], 'w')
     for fname in data.previously_included: