Cast unused parameter to void.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132641 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm-c/Core.h

@@ -1166,6 +1166,7 @@ namespace llvm {
     for (LLVMValueRef *I = Vals, *E = Vals + Length; I != E; ++I)
       cast<T>(*I);
     #endif
+    (void)Length;
     return reinterpret_cast<T**>(Vals);
   }