diff --git a/gfx/src/moz.build b/gfx/src/moz.build
index 0c8a95f165cb..13ecc2a95233 100644
--- a/gfx/src/moz.build
+++ b/gfx/src/moz.build
@@ -45,11 +45,10 @@ if CONFIG['MOZ_X11']:
         'X11Util.cpp',
     ]
 
-SOURCES += [
+UNIFIED_SOURCES += [
     'FilterSupport.cpp',
     'gfxCrashReporterUtils.cpp',
     'nsColor.cpp',
-    'nsDeviceContext.cpp',
     'nsFont.cpp',
     'nsFontMetrics.cpp',
     'nsRect.cpp',
@@ -61,6 +60,11 @@ SOURCES += [
     'nsTransform2D.cpp',
 ]
 
+# nsDeviceContext.cpp cannot be built in unified mode because it pulls in OS X system headers.
+SOURCES += [
+    'nsDeviceContext.cpp',
+]
+
 FAIL_ON_WARNINGS = True
 
 MSVC_ENABLE_PGO = True
diff --git a/gfx/src/nsScriptableRegion.h b/gfx/src/nsScriptableRegion.h
index 98fe828d77da..aa0faae15dc8 100644
--- a/gfx/src/nsScriptableRegion.h
+++ b/gfx/src/nsScriptableRegion.h
@@ -4,6 +4,9 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#ifndef nsScriptableRegion_h
+#define nsScriptableRegion_h
+
 #include "nsIScriptableRegion.h"
 #include "gfxCore.h"
 #include "nsISupports.h"
@@ -21,3 +24,5 @@ public:
 private:
 	nsIntRegion mRegion;
 };
+
+#endif