diff --git a/compat/nedmalloc/malloc.c.h b/compat/nedmalloc/malloc.c.h
index bf70037b4b..b833ff9225 100644
--- a/compat/nedmalloc/malloc.c.h
+++ b/compat/nedmalloc/malloc.c.h
@@ -1802,9 +1802,10 @@ struct win32_mlock_t
   volatile long threadid;
 };
 
+static inline int return_0(int i) { return 0; }
 #define MLOCK_T               struct win32_mlock_t
 #define CURRENT_THREAD        win32_getcurrentthreadid()
-#define INITIAL_LOCK(sl)      (memset(sl, 0, sizeof(MLOCK_T)), 0)
+#define INITIAL_LOCK(sl)      (memset(sl, 0, sizeof(MLOCK_T)), return_0(0))
 #define ACQUIRE_LOCK(sl)      win32_acquire_lock(sl)
 #define RELEASE_LOCK(sl)      win32_release_lock(sl)
 #define TRY_LOCK(sl)          win32_try_lock(sl)
diff --git a/compat/win32/pthread.h b/compat/win32/pthread.h
index d3dd872918..20b35a283c 100644
--- a/compat/win32/pthread.h
+++ b/compat/win32/pthread.h
@@ -18,7 +18,10 @@
  */
 #define pthread_mutex_t CRITICAL_SECTION
 
-#define pthread_mutex_init(a,b) (InitializeCriticalSection((a)), 0)
+static inline int return_0(int i) {
+	return 0;
+}
+#define pthread_mutex_init(a,b) return_0((InitializeCriticalSection((a)), 0))
 #define pthread_mutex_destroy(a) DeleteCriticalSection((a))
 #define pthread_mutex_lock EnterCriticalSection
 #define pthread_mutex_unlock LeaveCriticalSection