This patch follows glibc. Original commit message:
Author: Florian Weimer <fweimer@redhat.com>
Date: Thu, 14 Apr 2016 06:54:57 +0000
Remove union wait [BZ #19613]
The overloading approach in the W* macros was incompatible with
integer expressions of a type different from int. Applications
using union wait and these macros will have to migrate to the
POSIX-specified int status type.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>