diff --git a/libc/stdio/fileext.h b/libc/stdio/fileext.h
index 209815a..6cacc0f 100644
--- a/libc/stdio/fileext.h
+++ b/libc/stdio/fileext.h
@@ -61,7 +61,11 @@
 	_UB(fp)._base = NULL; \
 	_UB(fp)._size = 0; \
 	WCIO_INIT(fp); \
-	_FLOCK(fp).value = __PTHREAD_RECURSIVE_MUTEX_INIT_VALUE; \
+	pthread_mutexattr_t attr; \
+	pthread_mutexattr_init(&attr); \
+	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE); \
+	pthread_mutex_init(&_FLOCK(fp), &attr); \
+	pthread_mutexattr_destroy(&attr); \
 	_EXT(fp)->_stdio_handles_locking = true; \
 } while (0)