Remove AC_HEADER_SYS_WAIT

GNU autoconf documentation marks this macro as obsolescent, as
current systems are compatible with POSIX.

Simplify code to unconditionally include <sys/wait.h>, and don't
redefine WIFEXITSTATUS() and WIFEXITED(), since they are mandated
by POSIX.

Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>

configure.ac

@@ -37,7 +37,6 @@ AM_PROG_LIBTOOL
 dnl Checks for libraries.
 
 dnl Checks for header files.
-AC_HEADER_SYS_WAIT
 AC_HEADER_STDBOOL
 
 AC_CHECK_HEADERS(crypt.h errno.h fcntl.h limits.h unistd.h sys/time.h utmp.h \

lib/defines.h

@@ -68,15 +68,7 @@ extern char * textdomain (const char * domainname);
 
 #include <sys/stat.h>
 #include <sys/types.h>
-#if HAVE_SYS_WAIT_H
-# include <sys/wait.h>
-#endif
-#ifndef WEXITSTATUS
-# define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8)
-#endif
-#ifndef WIFEXITED
-# define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
-#endif
+#include <sys/wait.h>
 
 #if HAVE_UNISTD_H
 # include <unistd.h>