Format aapt warnings the same way as other compiler warnings
('warning: ' instead of 'WARNING: ' or 'WARNING ')
diff --git a/tools/aapt/XMLNode.cpp b/tools/aapt/XMLNode.cpp
index 832ba6c..6daa0d2 100644
--- a/tools/aapt/XMLNode.cpp
+++ b/tools/aapt/XMLNode.cpp
@@ -220,7 +220,7 @@
             spanStack.pop();
 
             if (empty) {
-                fprintf(stderr, "%s:%d: WARNING: empty '%s' span found in text '%s'\n",
+                fprintf(stderr, "%s:%d: warning: empty '%s' span found in text '%s'\n",
                         fileName, inXml->getLineNumber(),
                         String8(spanTag).string(), String8(*outString).string());