cgen,os: fix tcc __attribute__, fix os.notify (followup to #25779) (#25804)

Author: kbkpbot

vlib/os/notify/backend_linux.c.v

@@ -3,7 +3,7 @@ module notify
 import time
 import os
 
-#insert "@VEXEROOT/vlib/os/notify/epoll.h"
+#include <sys/epoll.h>
 
 pub struct C.epoll_event {
 	events u32

vlib/os/notify/epoll.h

@@ -309,6 +309,11 @@ typedef int (*qsort_callback_func)(const void*, const void*);
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h> // for va_list
+#if defined(__TINYC__)
+// https://lists.nongnu.org/archive/html/tinycc-devel/2025-10/msg00007.html
+// gnu headers use to #define __attribute__ to empty for non-gcc compilers
+#undef __attribute__
+#endif
 #ifdef __TERMUX__
 #if defined __BIONIC_AVAILABILITY_GUARD && __BIONIC_AVAILABILITY_GUARD(28)
 #else