-#include <sys/types.h>
-#include <unistd.h>
+#define _GNU_SOURCE
#include <grp.h>
#include <limits.h>
-int getgrouplist(const char *, gid_t, gid_t *, int *);
-int setgroups(size_t, const gid_t *);
-
int initgroups(const char *user, gid_t gid)
{
gid_t groups[NGROUPS_MAX];