Reapply portability fixes, this time without 64 bit system bug.

src/runtime.cc

Index: src/runtime.cc
===================================================================
--- src/runtime.cc	(revision 1572)
+++ src/runtime.cc	(working copy)
@@ -1723,7 +1723,7 @@
   // Number of parts added by compiled replacement plus preceeding string
   // and possibly suffix after last match.
   const int parts_added_per_loop = compiled_replacement.parts() + 2;
-  bool matched;
+  bool matched = true;
   do {
     ASSERT(last_match_info_handle->HasFastElements());
     // Increase the capacity of the builder before entering local handle-scope,