don't exclude _xdg(_unittest)?\\.(h|cc) on OpenBSD either

build/common.gypi

 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 1242 matching lines @@
               ['exclude', '(^|/)x11_[^/]*\\.(h|cc)$'],
             ],
           }],
           ['toolkit_uses_gtk!=1', {
             'sources/': [
               ['exclude', '_gtk(_unittest)?\\.(h|cc)$'],
               ['exclude', '(^|/)gtk/'],
               ['exclude', '(^|/)gtk_[^/]*\\.(h|cc)$'],
             ],
           }],
-          ['OS!="linux"', {
+          ['OS!="linux" and OS!="openbsd"', {
             'sources/': [
               ['exclude', '_xdg(_unittest)?\\.(h|cc)$'],
             ],
           }],
           ['use_wayland!=1', {
             'sources/': [
               ['exclude', '_(wayland)(_unittest)?\\.(h|cc)$'],
               ['exclude', '(^|/)wayland/'],
               ['exclude', '(^|/)(wayland)_[^/]*\\.(h|cc)$'],
             ],
@@ skipping 1332 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }