buildman: Use oldconfig when adjusting the config

We cannot be sure that the new config is consistent, particularly when
changing a major item like CONFIG_CMDLINE. Use 'make oldconfig' to
check that and avoid any such problems.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/buildman/builder.py

@@ -480,7 +480,7 @@ class Builder:
         Args:
             commit: Commit object that is being built
             brd: Board object that is being built
-            stage: Stage that we are at (mrproper, config, build)
+            stage: Stage that we are at (mrproper, config, oldconfig, build)
             cwd: Directory where make should be run
             args: Arguments to pass to make
             kwargs: Arguments to pass to command.run_pipe()

tools/buildman/builderthread.py

@@ -426,6 +426,12 @@ class BuilderThread(threading.Thread):
 
         # Now do the build, if everything looks OK
         if result.return_code == 0:
+            if adjust_cfg:
+                oldc_args = list(args) + ['oldconfig']
+                oldc_result = self.make(commit, brd, 'oldconfig', cwd,
+                                        *oldc_args, env=env)
+                if oldc_result.return_code:
+                    return oldc_result
             result = self._build(commit, brd, cwd, args, env, cmd_list,
                                  config_only)
             if adjust_cfg:

tools/buildman/func_test.py

@@ -439,6 +439,8 @@ class TestFunctional(unittest.TestCase):
             tools.write_file(fname, b'CONFIG_SOMETHING=1')
             return command.CommandResult(return_code=0,
                     combined='Test configuration complete')
+        elif stage == 'oldconfig':
+            return command.CommandResult(return_code=0)
         elif stage == 'build':
             stderr = ''
             fname = os.path.join(cwd or '', out_dir, 'u-boot')
@@ -461,7 +463,7 @@ Some images are invalid'''
             return command.CommandResult(return_code=0)
 
         # Not handled, so abort
-        print('make', stage)
+        print('_HandleMake failure: make', stage)
         sys.exit(1)
 
     # Example function to print output lines