diff --git a/webapprt/win/moz.build b/webapprt/win/moz.build
index 9b37940d17a..9c159253e53 100644
--- a/webapprt/win/moz.build
+++ b/webapprt/win/moz.build
@@ -14,8 +14,6 @@ SOURCES += [
 ]
 
 DEFINES['XPCOM_GLUE'] = True
-if CONFIG['DEBUG']:
-    DEFINES['DEBUG'] = True
 
 DEFINES['APP_VERSION'] = CONFIG['FIREFOX_VERSION']
 
diff --git a/widget/cocoa/moz.build b/widget/cocoa/moz.build
index 0979cb909ff..5e918d25260 100644
--- a/widget/cocoa/moz.build
+++ b/widget/cocoa/moz.build
@@ -70,7 +70,7 @@ SOURCES += [
     'nsNativeThemeCocoa.mm',
 ]
 
-if not CONFIG['RELEASE_BUILD'] or CONFIG['DEBUG']:
+if not CONFIG['RELEASE_BUILD'] or CONFIG['MOZ_DEBUG']:
     SOURCES += [
         'nsSandboxViolationSink.mm',
     ]
diff --git a/xulrunner/app/moz.build b/xulrunner/app/moz.build
index f8b75599c3f..0195a439906 100644
--- a/xulrunner/app/moz.build
+++ b/xulrunner/app/moz.build
@@ -13,7 +13,7 @@ SOURCES += [
 ]
 
 DEFINES['XULRUNNER_PROGNAME'] = '"xulrunner"'
-if CONFIG['DEBUG']:
+if CONFIG['MOZ_DEBUG']:
     DEFINES['DEBUG'] = True
 
 LOCAL_INCLUDES += [