diff --git a/dom/system/moz.build b/dom/system/moz.build
index fc8cf533b0..cb0818b345 100644
--- a/dom/system/moz.build
+++ b/dom/system/moz.build
@@ -30,7 +30,7 @@ EXPORTS.mozilla += [
     'OSFileConstants.h',
 ]
 
-UNIFIED_SOURCES += [
+SOURCES += [
     'nsDeviceSensors.cpp',
     'OSFileConstants.cpp',
 ]