Make a bunch of symbols private.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138025 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ScheduleDAG.cpp b/lib/CodeGen/ScheduleDAG.cpp
index fc68db9..1e9b5c8 100644
--- a/lib/CodeGen/ScheduleDAG.cpp
+++ b/lib/CodeGen/ScheduleDAG.cpp
@@ -26,7 +26,7 @@
 using namespace llvm;
 
 #ifndef NDEBUG
-cl::opt<bool> StressSchedOpt(
+static cl::opt<bool> StressSchedOpt(
   "stress-sched", cl::Hidden, cl::init(false),
   cl::desc("Stress test instruction scheduling"));
 #endif