Subzero: Emit ARM build-attributes in the file scope (as header).

src/IceTargetLoweringARM32.h

Index: src/IceTargetLoweringARM32.h
diff --git a/src/IceTargetLoweringARM32.h b/src/IceTargetLoweringARM32.h
index 53c98951993af7a4d08d0d09230877f74bf250fb..61a5df700a924731d76e3bce6d526f61db551360 100644
--- a/src/IceTargetLoweringARM32.h
+++ b/src/IceTargetLoweringARM32.h
@@ -324,6 +324,25 @@ private:
   template <typename T> static void emitConstantPool(GlobalContext *Ctx);
 };
 
+class TargetHeaderARM32 : public TargetHeaderLowering {
+  TargetHeaderARM32() = delete;
+  TargetHeaderARM32(const TargetHeaderARM32 &) = delete;
+  TargetHeaderARM32 &operator=(const TargetHeaderARM32 &) = delete;
+
+public:
+  static TargetHeaderLowering *create(GlobalContext *Ctx) {
+    return new TargetHeaderARM32(Ctx);
+  }
+
+  void lower() final;
+
+protected:
+  explicit TargetHeaderARM32(GlobalContext *Ctx);
+
+private:
+  ~TargetHeaderARM32() final {}
+};
+
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGARM32_H