src/chfn,chpasswd,newusers: declare fatal_exit() NORETURN

Help static analyzers to understand fatal_exit() does never return.

src/chfn.c

@@ -57,7 +57,7 @@ static bool pw_locked = false;
  */
 
 /* local function prototypes */
-static void fail_exit (int code);
+NORETURN static void fail_exit (int code);
 NORETURN static void usage (int status);
 static bool may_change_field (int);
 static void new_fields (void);

src/chpasswd.c

@@ -61,7 +61,7 @@ static bool pw_locked = false;
 static bool spw_locked = false;
 
 /* local function prototypes */
-static void fail_exit (int code);
+NORETURN static void fail_exit (int code);
 NORETURN static void usage (int status);
 static void process_flags (int argc, char **argv);
 static void check_flags (void);

src/newusers.c

@@ -90,8 +90,8 @@ static bool sub_gid_locked = false;
 #endif				/* ENABLE_SUBIDS */
 
 /* local function prototypes */
-static void usage (int status);
-static void fail_exit (int);
+NORETURN static void usage (int status);
+NORETURN static void fail_exit (int);
 static int add_group (const char *, const char *, gid_t *, gid_t);
 static int get_user_id (const char *, uid_t *);
 static int add_user (const char *, uid_t, gid_t);