--- src/backend/storage/file/fd.c	2025-05-06 04:28:35.000000000 +0800
+++ src/backend/storage/file/fd.c	2025-07-30 06:43:30.000000000 +0800
@@ -111,6 +111,10 @@
 #define PG_FLUSH_DATA_WORKS 1
 #endif
 
+#ifndef O_DSYNC
+#define O_DSYNC 0
+#endif
+
 /*
  * We must leave some file descriptors free for system(), the dynamic loader,
  * and other code that tries to open files without consulting fd.c.  This