Add presubmit=no and werror=no flags to Makefile

tools/presubmit.py

Index: tools/presubmit.py
diff --git a/tools/presubmit.py b/tools/presubmit.py
index fda7ba96e5957a5b91c98f120af4c1708ed8c9a4..7af6e3d0d80e3a85c7606af692c8b1c249e78922 100755
--- a/tools/presubmit.py
+++ b/tools/presubmit.py
@@ -211,7 +211,12 @@ class CppLintProcessor(SourceFileProcessor):
     if exists(local_cpplint):
       command = ['python', local_cpplint, '--filter', filt] + join(files)
 
-    process = subprocess.Popen(command, stderr=subprocess.PIPE)
+    try:
+      process = subprocess.Popen(command, stderr=subprocess.PIPE)
+    except:
+      print('Error running cpplint.py. Please make sure you have depot_tools' +
+            ' in your $PATH. Lint check skipped.')
+      return True
     LINT_ERROR_PATTERN = re.compile(r'^(.+)[:(]\d+[:)]')
     while True:
       out_line = process.stderr.readline()