$-indexed printf params don't work on all of our architectures, turns out.

runtime/vm/parser_test.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 
 #include "vm/ast_printer.h"
 #include "vm/class_finalizer.h"
 #include "vm/debugger.h"
 #include "vm/longjump.h"
 #include "vm/object.h"
@@ skipping 194 matching lines @@
   DebuggerStackTrace* stack =
       Isolate::Current()->debugger()->StackTrace();
   intptr_t num_frames = stack->Length();
   const int kBufferLen = 2048;
   char* buffer = new char[kBufferLen];
   char* pos = buffer;
   LocalVarDescriptors& var_desc = LocalVarDescriptors::Handle();
   for (intptr_t i = 0; i < num_frames; i++) {
     ActivationFrame* frame = stack->FrameAt(i);
     var_desc = frame->code().var_descriptors();
-    const char* var_str = var_desc.ToCString();
-    char* edited_var_str = SkipIndex(var_str);
+    const char* var_str = SkipIndex(var_desc.ToCString());
     pos += OS::SNPrint(pos, (kBufferLen - (pos - buffer)),
                        "%s\n%s",
                        frame->function().ToQualifiedCString(),
-                       (edited_var_str != NULL ? edited_var_str :var_str));
-    delete [] edited_var_str;
+                       var_str);
+    delete [] var_str;
   }
   pos[0] = '\0';
   saved_vars = buffer;
 }
 
 
 // Uses the debugger to pause the program and capture the variable
 // descriptors for all frames on the stack.
 static const char* CaptureVarsAtLine(Dart_Handle lib,
                                      const char* entry,
@@ skipping 251 matching lines @@
       //   https://code.google.com/p/dart/issues/detail?id=18561
       "::.outer\n"
       " 0 StackVar      scope=3   begin=9   end=50  name=i\n"
       " 1 ContextLevel  level=1   scope=4   begin=20  end=50\n"
       " 2 ContextVar    level=1   begin=23  end=50  name=value\n"
       " 3 StackVar      scope=4   begin=30  end=50  name=inner\n",
       CaptureVarsAtLine(lib, "outer", 5));
 }
 
 }  // namespace dart