Fix Debian compilation error

runtime/vm/compiler.cc

 // Copyright (c) 2012, 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/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 1547 matching lines @@
 #ifdef DART_PRECOMPILER
   if (FLAG_precompiled_mode) {
     return Precompiler::EvaluateStaticInitializer(field);
   }
 #endif
   ASSERT(field.is_static());
   // The VM sets the field's value to transiton_sentinel prior to
   // evaluating the initializer value.
   ASSERT(field.StaticValue() == Object::transition_sentinel().raw());
   LongJumpScope jump;
-  Thread* thread = Thread::Current();
   if (setjmp(*jump.Set()) == 0) {
+    Thread* const thread = Thread::Current();
     NoOOBMessageScope no_msg_scope(thread);
     NoReloadScope no_reload_scope(thread->isolate(), thread);
     // Under lazy compilation initializer has not yet been created, so create
     // it now, but don't bother remembering it because it won't be used again.
     ASSERT(!field.HasPrecompiledInitializer());
-    Thread* const thread = Thread::Current();
     Function& initializer = Function::Handle(thread->zone());
     {
       NOT_IN_PRODUCT(
         VMTagScope tagScope(thread, VMTag::kCompileUnoptimizedTagId);
         TimelineDurationScope tds(thread, Timeline::GetCompilerStream(),
                                   "CompileStaticInitializer");
         if (tds.enabled()) {
           tds.SetNumArguments(1);
           tds.CopyArgument(0, "field", field.ToCString());
         }
@@ skipping 596 matching lines @@
 
 
 bool BackgroundCompiler::IsDisabled() {
   UNREACHABLE();
   return true;
 }
 
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart