Make "root" flag configurable via CPPLINT.CFG

cpplint/cpplint.py

@@ -142,6 +142,7 @@
       filter=+filter1,-filter2,...
       exclude_files=regex
       linelength=80
+      root=subdir
 
     "set noparent" option prevents cpplint from traversing directory tree
     upwards looking for more .cfg files in parent directories. This option
@@ -157,6 +158,9 @@
 
     "linelength" allows to specify the allowed line length for the project.
 
+    The "root" option is similar in function to the --root flag (see example
+    above).
+
     CPPLINT.cfg has an effect on files in the same directory and all
     sub-directories, unless overridden by a nested configuration file.
 
@@ -1666,7 +1670,7 @@ def GetHeaderGuardCPPVariable(filename):
   filename = re.sub(r'/\.flymake/([^/]*)$', r'/\1', filename)
   # Replace 'c++' with 'cpp'.
   filename = filename.replace('C++', 'cpp').replace('c++', 'cpp')
-  
+
   fileinfo = FileInfo(filename)
   file_path_from_root = fileinfo.RepositoryName()
   if _root:
@@ -4794,7 +4798,7 @@ def CheckLanguage(filename, clean_lines, linenum, file_extension,
 
   # Make Windows paths like Unix.
   fullname = os.path.abspath(filename).replace('\\', '/')
-  
+
   # Perform other checks now that we are sure that this is not an include line
   CheckCasts(filename, clean_lines, linenum, error)
   CheckGlobalStatic(filename, clean_lines, linenum, error)
@@ -6034,7 +6038,7 @@ def ProcessFileData(filename, file_extension, lines, error,
   nesting_state.CheckCompletedBlocks(filename, error)
 
   CheckForIncludeWhatYouUse(filename, clean_lines, include_state, error)
-  
+
   # Check that the .cc file has included its header if it exists.
   if file_extension == 'cc':
     CheckHeaderFileIncluded(filename, include_state, error)
@@ -6103,6 +6107,9 @@ def ProcessConfigOverrides(filename):
                 _line_length = int(val)
             except ValueError:
                 sys.stderr.write('Line length must be numeric.')
+          elif name == 'root':
+            global _root
+            _root = val
           else:
             sys.stderr.write(
                 'Invalid configuration option (%s) in file %s\n' %