Give some helper classes/functions internal linkage. NFC.

llvm-svn: 287462
diff --git a/llvm/lib/Target/SystemZ/SystemZHazardRecognizer.cpp b/llvm/lib/Target/SystemZ/SystemZHazardRecognizer.cpp
index 26284df..fe4b52b 100644
--- a/llvm/lib/Target/SystemZ/SystemZHazardRecognizer.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZHazardRecognizer.cpp
@@ -31,10 +31,10 @@
 // This is the limit of processor resource usage at which the
 // scheduler should try to look for other instructions (not using the
 // critical resource).
-cl::opt<int> ProcResCostLim("procres-cost-lim", cl::Hidden,
-                            cl::desc("The OOO window for processor "
-                                     "resources during scheduling."),
-                            cl::init(8));
+static cl::opt<int> ProcResCostLim("procres-cost-lim", cl::Hidden,
+                                   cl::desc("The OOO window for processor "
+                                            "resources during scheduling."),
+                                   cl::init(8));
 
 SystemZHazardRecognizer::
 SystemZHazardRecognizer(const MachineSchedContext *C) : DAG(nullptr),