Fix for unused-lambda-capture warning

CMakeLists.txt

@@ -203,6 +203,7 @@ else()
     set_cpp_flag("-Werror=reorder")
     set_cpp_flag("-Werror=sign-compare")
     set_cpp_flag("-Werror=missing-braces")
+    set_cpp_flag("-Werror=unused-lambda-capture")
     set_cpp_flag("-fno-exceptions")
 
     # Remove xor, and, or and friends from the list of keywords, they are used

third_party/subzero/src/IceTargetLowering.h

@@ -532,6 +532,7 @@ protected:
 
       auto makeExtractThunk = [this, Index, NumElements](Operand *Src) {
         return [this, Index, NumElements, Src]() {
+          (void)NumElements;
           assert(typeNumElements(Src->getType()) == NumElements);
 
           const auto ElementTy = typeElementType(Src->getType());