Back out "Enable -Wunused-variable in glean/PACKAGE"

Summary: Original Phabricator Diff: D66847527

Reviewed By: bochko, malanka

Differential Revision: D67276738

fbshipit-source-id: eba0357ac006e6a820a6eb0c60c76f6f034174f8

glean/rocksdb/database-impl.cpp

@@ -269,15 +269,16 @@ struct SeekIterator final : rts::FactIterator {
   Fact::Ref get(Demand demand) override {
     if (iter_->Valid()) {
       auto key = input(iter_->key());
-      assert(key.fixed<Pid>() == type_);
+      auto ty = key.fixed<Pid>();
+      assert(ty == type_);
       auto value = input(iter_->value());
       auto id = value.fixed<Id>();
       assert(value.empty());
 
       if (demand == KeyOnly) {
         return Fact::Ref{id, type_, Fact::Clause::fromKey(key.bytes())};
       } else {
-        [[maybe_unused]] auto found = db_->lookupById(id, slice_);
+        auto found = db_->lookupById(id, slice_);
         assert(found);
         return decomposeFact(id, slice_);
       }

glean/rts/stacked.h

@@ -160,11 +160,12 @@ struct Stacked<Define> final : StackedBase<Define> {
         //       similar). This means that there is no need to check against the
         //       value stored in the database as that must be empty, too.
         if (clause.value_size != 0) {
-          assert(base->factById(id, [&](auto, auto found) {
+          bool found = base->factById(id, [&](auto, auto found) {
             if (clause.value() != found.value()) {
               id = Id::invalid();
             }
-          }));
+          });
+          assert(found);
         }
         return id;
       }