fix prototypes/signature for setgroups, etc.

include/grp.h

@@ -28,6 +28,12 @@ struct group  *getgrent(void);
 void           endgrent(void);
 void           setgrent(void);
 
+#ifdef _GNU_SOURCE
+int getgrouplist(const char *, gid_t, gid_t *, int *);
+int setgroups(size_t, const gid_t *);
+int initgroups(const char *, gid_t);
+#endif
+
 #ifdef __cplusplus
 }
 #endif

include/unistd.h

@@ -154,7 +154,7 @@ int getpagesize(void);
 int sethostname(const char *, size_t);
 int usleep(unsigned);
 unsigned ualarm(unsigned, unsigned);
-int setgroups(int, const gid_t []);
+int setgroups(size_t, const gid_t []);
 int setresuid(uid_t, uid_t, uid_t);
 int setresgid(gid_t, gid_t, gid_t);
 #endif

src/linux/setgroups.c

@@ -1,7 +1,7 @@
 #include <unistd.h>
 #include "syscall.h"
 
-int setgroups(int count, const gid_t list[])
+int setgroups(size_t count, const gid_t list[])
 {
 	return syscall(SYS_setgroups, count, list);
 }