diff --git a/src/option.h b/src/option.h
index 2b7e80d..9aa2aaa 100644
--- a/src/option.h
+++ b/src/option.h
@@ -467,7 +467,9 @@
 # define FDO_JUMP		0x400
 #endif
 EXTERN char_u	*p_fp;		/* 'formatprg' */
+#ifdef HAVE_FSYNC
 EXTERN int	p_fs;		/* 'fsync' */
+#endif
 EXTERN int	p_gd;		/* 'gdefault' */
 #ifdef FEAT_PRINTER
 EXTERN char_u	*p_pdev;	/* 'printdevice' */