patch 8.0.1335: writefile() using fsync() may give an error.

Problem:    Writefile() using fsync() may give an error for a device.
            (Yasuhiro Matsumoto)
Solution:   Ignore fsync() failing. (closes #2373)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 8d288e0..76c5768 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -13449,8 +13449,10 @@
 	if (write_list(fd, list, binary) == FAIL)
 	    ret = -1;
 #ifdef HAVE_FSYNC
-	else if (do_fsync && fsync(fileno(fd)) != 0)
-	    EMSG(_(e_fsync));
+	else if (do_fsync)
+	    /* Ignore the error, the user wouldn't know what to do about it.
+	     * May happen for a device. */
+	    ignored = fsync(fileno(fd));
 #endif
 	fclose(fd);
     }