Issue #80 - reinstated unified building for some large chunks of our code.

This should reduce compile complexity saving time and reducing linker stress.

dom/events/moz.build

@@ -73,7 +73,7 @@ EXPORTS.mozilla.dom += [
     'XULCommandEvent.h',
 ]
 
-SOURCES += [
+UNIFIED_SOURCES += [
     'AnimationEvent.cpp',
     'AsyncEventDispatcher.cpp',
     'BeforeAfterKeyboardEvent.cpp',
@@ -95,7 +95,6 @@ SOURCES += [
     'EventDispatcher.cpp',
     'EventListenerManager.cpp',
     'EventListenerService.cpp',
-    'EventStateManager.cpp',
     'EventTarget.cpp',
     'FocusEvent.cpp',
     'ImageCaptureError.cpp',
@@ -125,6 +124,11 @@ SOURCES += [
     'XULCommandEvent.cpp',
 ]
 
+# nsEventStateManager.cpp should be built separately because of Mac OS X headers.
+SOURCES += [
+    'EventStateManager.cpp',
+]
+
 include('/ipc/chromium/chromium-config.mozbuild')
 
 FINAL_LIBRARY = 'xul'