Fix compiling with dietlibc:
../libkmod/libkmod-module.c:858:2: warning: implicit declaration of function 'WEXITSTATUS' [-Wimplicit-function-declaration]
../libkmod/libkmod-module.c:858:2: warning: nested extern declaration of 'WEXITSTATUS' [-Wnested-externs]
(...)
kmod-modprobe.c:(.text.command_do+0x157): undefined reference to `WEXITSTATUS'
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
+#include <sys/wait.h>
#include <string.h>
#include <fnmatch.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/utsname.h>
+#include <sys/wait.h>
#include <unistd.h>
#include <syslog.h>
#include <limits.h>