[PATCH 2/2] not-cancel.h: Support testing fortify build with Clang

[H.J. Lu]

When Clang is used to test fortify glibc build configured with

--enable-fortify-source=N

clang issues errors like

In file included from tst-rfc3484.c:60:
In file included from ./getaddrinfo.c:81:
../sysdeps/unix/sysv/linux/not-cancel.h:36:10: error: reference to overloaded function could not be resolved; did you mean to call it?
   36 | __typeof (open64) __open64_nocancel;
      |          ^~~~~~~~
../include/bits/../../io/bits/fcntl2.h:127:1: note: possible target for call
  127 | open64 (__fortify_clang_overload_arg (const char *, ,__path), int __oflag,
      | ^
../include/bits/../../io/bits/fcntl2.h:118:1: note: possible target for call
  118 | open64 (__fortify_clang_overload_arg (const char *, ,__path), int __oflag)
      | ^
../include/bits/../../io/bits/fcntl2.h:114:1: note: possible target for call
  114 | open64 (const char *__path, int __oflag, mode_t __mode, ...)
      | ^
../io/fcntl.h:219:12: note: possible target for call
  219 | extern int open64 (const char *__file, int __oflag, ...) __nonnull ((1));
      |            ^

because clang fortify support for functions with variable arguments relies
on function overload.  Update not-cancel.h to avoid __typeof on functions
with variable arguments.

Co-Authored-By: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
---
 sysdeps/unix/sysv/linux/not-cancel.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/not-cancel.h b/sysdeps/unix/sysv/linux/not-cancel.h
index 62363c1b0f..ece329711b 100644
--- a/sysdeps/unix/sysv/linux/not-cancel.h
+++ b/sysdeps/unix/sysv/linux/not-cancel.h
@@ -30,16 +30,16 @@
 #include <sys/random.h>
 
 /* Non cancellable open syscall.  */
-__typeof (open) __open_nocancel;
+extern int __open_nocancel (const char *, int, ...);
 
 /* Non cancellable open syscall (LFS version).  */
-__typeof (open64) __open64_nocancel;
+extern int __open64_nocancel (const char *, int, ...);
 
 /* Non cancellable openat syscall.  */
-__typeof (openat) __openat_nocancel;
+extern int __openat_nocancel (int fd, const char *, int, ...);
 
 /* Non cacellable openat syscall (LFS version).  */
-__typeof (openat64) __openat64_nocancel;
+extern int __openat64_nocancel (int fd, const char *, int, ...);
 
 /* Non cancellable read syscall.  */
 __typeof (__read) __read_nocancel;
@@ -54,7 +54,7 @@ __typeof (__write) __write_nocancel;
 __typeof (__close) __close_nocancel;
 
 /* Uncancelable fcntl.  */
-__typeof (__fcntl) __fcntl64_nocancel;
+int __fcntl64_nocancel (int, int, ...);
 
 #if IS_IN (libc) || IS_IN (rtld)
 hidden_proto (__open_nocancel)
-- 
2.47.1