Add error checking to aapt for split generation

Change-Id: Ica627db6a671f6a6c35f98bfd9c03598ffe103ce
diff --git a/tools/aapt/SourcePos.cpp b/tools/aapt/SourcePos.cpp
index ae25047..3864320 100644
--- a/tools/aapt/SourcePos.cpp
+++ b/tools/aapt/SourcePos.cpp
@@ -141,6 +141,12 @@
 }
 
 bool
+SourcePos::operator<(const SourcePos& rhs) const
+{
+    return (file < rhs.file) || (line < rhs.line);
+}
+
+bool
 SourcePos::hasErrors()
 {
     return g_errors.size() > 0;