Uses SNPRINT macro where possible. Otherwise uses #define for format.

runtime/vm/zone.h

Index: runtime/vm/zone.h
diff --git a/runtime/vm/zone.h b/runtime/vm/zone.h
index 4850e5eb321d67863cd7d6b587a016148e69c911..361e6e28c26ff56e2d1c0987039d0ddeab681fb9 100644
--- a/runtime/vm/zone.h
+++ b/runtime/vm/zone.h
@@ -46,9 +46,12 @@ class Zone {
   // Make a copy of the string in the zone allocated area.
   char* MakeCopyOfString(const char* str);
 
+  // TODO(zra): Remove these calls and replace them with calls to OS::SCreate
+  // and OS::VSCreate.
+  // These calls are deprecated. Do not add further calls to these functions.
+  // instead use OS::SCreate and OS::VSCreate.
   // Make a zone-allocated string based on printf format and args.
   char* PrintToString(const char* format, ...) PRINTF_ATTRIBUTE(2, 3);
-
   char* VPrint(const char* format, va_list args);
 
   // Compute the total size of this zone. This includes wasted space that is