Fix unused parameters and variables

llvm-svn: 290459
diff --git a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
index cde9db4..af065b8 100644
--- a/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
@@ -44,7 +44,7 @@
 
 
 template <typename Input1, typename Input2 = Input1>
-constexpr bool do_test(int dummy = 0)
+constexpr bool do_test(int = 0)
 {
     using S1 = typename std::make_signed<Input1>::type;
     using S2 = typename std::make_signed<Input2>::type;