pre-upload: Don't enforce 80 chars for include guards

Avoid enforcing this limit on include guard definitions in C/C++
header files, as they can be quite long due to file structure.

This case is already skipped by the C++ linter (cpplint.py), so
this CL adds consistency by skipping this in the generic linter too.

BUG=none
TEST=run the script on a header file with "#ifndef" directive
     followed by a long name

Change-Id: I1efa7f9a152b11cc47b5a77b8399e7d81ef5dc50
Reviewed-on: https://chromium-review.googlesource.com/1087051
Commit-Ready: Maksim Ivanov <emaxx@chromium.org>
Tested-by: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/pre-upload.py b/pre-upload.py
index 4c6b783..8e9ca14 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -457,7 +457,7 @@
   MAX_LEN = 80
   SKIP_REGEXP = re.compile('|'.join([
       r'https?://',
-      r'^#\s*(define|include|import|pragma|if|endif)\b']))
+      r'^#\s*(define|include|import|pragma|if|ifndef|endif)\b']))
 
   included, excluded = _parse_common_inclusion_options(options)
   files = _filter_files(_get_affected_files(commit),