[PATCH roland/waitpid] Fix __waitpid_nocancel link error

[Roland McGrath <roland at hack dot frob dot com>]

> Well, I am not getting that error anymore but now my MIPS build dies
> while linking libc.so:
> 
> /local/home/sellcey/nightly/obj-mips-mti-linux-gnu/glibc/obj_default/libc_pic.os: In function `_IO_new_proc_close':
> /local/home/sellcey/nightly/src/glibc/libio/iopopen.c:347: undefined reference to `__waitpid_nocancel'
> /local/home/sellcey/nightly/src/glibc/libio/iopopen.c:345: undefined reference to `__waitpid_nocancel'
> /local/home/sellcey/nightly/install-mips-mti-linux-gnu/lib/gcc/mips-mti-linux-gnu/4.10.0/../../../../mips-mti-linux-gnu/bin/ld: /local/home/sellcey/nightly/obj-mips-mti-linux-gnu/glibc/obj_default/libc.so: hidden symbol `__waitpid_nocancel' isn't defined
> /local/home/sellcey/nightly/install-mips-mti-linux-gnu/lib/gcc/mips-mti-linux-gnu/4.10.0/../../../../mips-mti-linux-gnu/bin/ld: final link failed: Bad value
> collect2: error: ld returned 1 exit status

This is unrelated to fork.  It is due to my not-cancel.h change.  
I think the following patch will fix it.  Can you verify that?
(You can just use 'git checkout roland/waitpid' if you are otherwise
using unmodified trunk.)


Thanks,
Roland


	* sysdeps/unix/sysv/linux/not-cancel.h (waitpid_not_cancel):
	Use wait4 regardless of [__NR_waitpid].

--- a/sysdeps/unix/sysv/linux/not-cancel.h
+++ b/sysdeps/unix/sysv/linux/not-cancel.h
@@ -83,13 +83,8 @@ extern int __openat64_nocancel (int fd, const char *fname, int oflag,
   __fcntl_nocancel (fd, cmd, val)
 
 /* Uncancelable waitpid.  */
-#ifdef __NR_waitpid
-# define waitpid_not_cancel(pid, stat_loc, options) \
-  __waitpid_nocancel (pid, stat_loc, options)
-#else
-# define waitpid_not_cancel(pid, stat_loc, options) \
+#define waitpid_not_cancel(pid, stat_loc, options) \
   INLINE_SYSCALL (wait4, 4, pid, stat_loc, options, NULL)
-#endif
 
 /* Uncancelable pause.  */
 #define pause_not_cancel() \