Add 'const' qualifiers to static const char* variables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186371 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 60aa3a7..748259e 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -50,9 +50,9 @@
 #include "llvm/Target/TargetRegisterInfo.h"
 using namespace llvm;
 
-static const char *DWARFGroupName = "DWARF Emission";
-static const char *DbgTimerName = "DWARF Debug Writer";
-static const char *EHTimerName = "DWARF Exception Writer";
+static const char *const DWARFGroupName = "DWARF Emission";
+static const char *const DbgTimerName = "DWARF Debug Writer";
+static const char *const EHTimerName = "DWARF Exception Writer";
 
 STATISTIC(EmittedInsts, "Number of machine instrs printed");