silence minor gcc warning -Wempty-body

also silence fuzz test artefacts

lib/compress/zstdmt_compress.c

@@ -63,7 +63,9 @@ static unsigned long long GetCurrentClockTimeMicroseconds(void)
                 DEBUGLOG(MUTEX_WAIT_TIME_DLEVEL, "Thread took %llu microseconds to acquire mutex %s \n", \
                    elapsedTime, #mutex);          \
         }   }                                     \
-    } else pthread_mutex_lock(mutex);             \
+    } else {                                      \
+        pthread_mutex_lock(mutex);                \
+    }                                             \
 }
 
 #else

tests/fuzz/.gitignore

@@ -0,0 +1,5 @@
+# test artefacts
+corpora
+block_decompress
+block_round_trip
+simple_round_trip