Add missing macro SIGNATURE_BREAKPOINT.

Change-Id: I9e450b7b2ff34a3609a99bf8fe11e3efa88ccc30
diff --git a/vm/compiler/codegen/arm/Assemble.c b/vm/compiler/codegen/arm/Assemble.c
index e642c5c..493f95e 100644
--- a/vm/compiler/codegen/arm/Assemble.c
+++ b/vm/compiler/codegen/arm/Assemble.c
@@ -1105,6 +1105,7 @@
     return false;
 }
 
+#if defined(SIGNATURE_BREAKPOINT)
 /* Inspect the assembled instruction stream to find potential matches */
 static void matchSignatureBreakpoint(const CompilationUnit *cUnit,
                                      unsigned int size)
@@ -1132,6 +1133,7 @@
         }
     }
 }
+#endif
 
 /*
  * Translation layout in the code cache.  Note that the codeAddress pointer