3 files changed, 9 insertions, 5 deletions
diff --git a/upb/refcounted.c b/upb/refcounted.c
index cba535f..ca97d9f 100644
--- a/upb/refcounted.c
+++ b/upb/refcounted.c
@@ -35,7 +35,7 @@ const void *UPB_UNTRACKED_REF = &untracked_val;
 static void atomic_inc(uint32_t *a) { (*a)++; }
 static bool atomic_dec(uint32_t *a) { return --(*a) == 0; }
 
-#elif (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || __GNUC__ > 4 ///////////////////
+#elif defined(__GNUC__) || defined(__clang__) //////////////////////////////////
 
 static void atomic_inc(uint32_t *a) { __sync_fetch_and_add(a, 1); }
 static bool atomic_dec(uint32_t *a) { return __sync_sub_and_fetch(a, 1) == 0; }
diff --git a/upb/refcounted.h b/upb/refcounted.h
index 42251b1..3de4a12 100644
--- a/upb/refcounted.h
+++ b/upb/refcounted.h
@@ -21,10 +21,13 @@
 
 #include "upb/table.int.h"
 
-// Reference tracking is designed to be used with a tool like Valgrind; when
-// enabled, it will cause reference leaks to show up as actual memory leaks
-// that are attributed to the code that leaked the ref, *not* the code that
-// originally created the object.
+// Reference tracking will check ref()/unref() operations to make sure the
+// ref ownership is correct.  Where possible it will also make tools like
+// Valgrind attribute ref leaks to the code that took the leaked ref, not
+// the code that originally created the object.
+//
+// Enabling this requires the application to define upb_lock()/upb_unlock()
+// functions that acquire/release a global mutex (or #define UPB_THREAD_UNSAFE).
 #ifndef NDEBUG
 #define UPB_DEBUG_REFS
 #endif
diff --git a/upb/table.c b/upb/table.c
index e0cac64..3fd4b0f 100644
--- a/upb/table.c
+++ b/upb/table.c
@@ -112,6 +112,7 @@ static bool lookup(const upb_table *t, upb_tabkey key, upb_value *v,
 // The given key must not already exist in the table.
 static void insert(upb_table *t, upb_tabkey key, upb_value val,
                    hashfunc_t *hash, eqlfunc_t *eql) {
+  UPB_UNUSED(eql);
   assert(findentry(t, key, hash, eql) == NULL);
   assert(val.ctype == t->ctype);
   t->count++;