stdint types all the way!

Change-Id: I4e4ef3a2002fc59ebd9097087f150eaf3f2a7e08
diff --git a/compiler/utils/arm64/assembler_arm64.h b/compiler/utils/arm64/assembler_arm64.h
index 373fd34..ef83334 100644
--- a/compiler/utils/arm64/assembler_arm64.h
+++ b/compiler/utils/arm64/assembler_arm64.h
@@ -214,7 +214,7 @@
   void AddConstant(Register rd, Register rn, int32_t value, vixl::Condition cond = vixl::al);
 
   // Vixl assembler.
-  vixl::MacroAssembler* vixl_masm_;
+  vixl::MacroAssembler* const vixl_masm_;
 
   // List of exception blocks to generate at the end of the code cache.
   std::vector<Arm64Exception*> exception_blocks_;