Fix gcc build.

src/ast/prettyprinter.cc

Index: src/ast/prettyprinter.cc
diff --git a/src/ast/prettyprinter.cc b/src/ast/prettyprinter.cc
index 93bce313d9cd65ae37632af007514f16e50c755a..40a60fc601f871bf82503b0b44f356e83ae0db3f 100644
--- a/src/ast/prettyprinter.cc
+++ b/src/ast/prettyprinter.cc
@@ -886,7 +886,7 @@ void AstPrinter::VisitTryFinallyStatement(TryFinallyStatement* node) {
 void AstPrinter::PrintTryStatement(TryStatement* node) {
   PrintIndentedVisit("TRY", node->try_block());
   PrintIndented("CATCH PREDICTION");
-  const char* prediction;
+  const char* prediction = "";
   switch (node->catch_prediction()) {
     case HandlerTable::UNCAUGHT:
       prediction = "UNCAUGHT";