Make ARM RegNames[] static like X86 (no ARM syms in X86-only build).

src/IceTargetLoweringARM32.cpp

Index: src/IceTargetLoweringARM32.cpp
diff --git a/src/IceTargetLoweringARM32.cpp b/src/IceTargetLoweringARM32.cpp
index e09a85fff0b41b4fd692cba9b6f928c6da20099b..c9d61af8c2070ed121ca0a48319765bb53ab1b59 100644
--- a/src/IceTargetLoweringARM32.cpp
+++ b/src/IceTargetLoweringARM32.cpp
@@ -348,17 +348,17 @@ bool TargetARM32::doBranchOpt(Inst *I, const CfgNode *NextNode) {
   return false;
 }
 
-IceString TargetARM32::RegNames[] = {
+IceString TargetARM32::getRegName(SizeT RegNum, Type Ty) const {
+  assert(RegNum < RegARM32::Reg_NUM);
+  (void)Ty;
+  static const char *RegNames[] = {
 #define X(val, encode, name, scratch, preserved, stackptr, frameptr, isInt,    \
           isFP)                                                                \
   name,
-    REGARM32_TABLE
+      REGARM32_TABLE
 #undef X
-};
+  };
 
-IceString TargetARM32::getRegName(SizeT RegNum, Type Ty) const {
-  assert(RegNum < RegARM32::Reg_NUM);
-  (void)Ty;
   return RegNames[RegNum];
 }