The 'l' length modifier makes sense with the scanlist conversion specifier.

llvm-svn: 148586
diff --git a/clang/lib/Analysis/FormatString.cpp b/clang/lib/Analysis/FormatString.cpp
index 207f773..fb52742 100644
--- a/clang/lib/Analysis/FormatString.cpp
+++ b/clang/lib/Analysis/FormatString.cpp
@@ -531,6 +531,7 @@
         case ConversionSpecifier::nArg:
         case ConversionSpecifier::cArg:
         case ConversionSpecifier::sArg:
+        case ConversionSpecifier::ScanListArg:
           return true;
         default:
           return false;