Fix some compilation warnings:

* src/login.c: "dereferencing type-punned pointer will break
   strict-aliasing rules", add a variable indirection: ptr_pam_user.
 * lib/commonio.c: do not initialize the sb stat structure.
 * lib/pwio.c, lib/shadowio.c, lib/sgroupio.c, lib/groupio.c:
   initialize the security context if WITH_SELINUX.
 * lib/nscd.c: The service argument is not const (used in the exec*
   parameters). This matches with the prototype definition.
 * src/groupmems.c: Avoid ++i when i is also used in the same line.
 * src/newusers.c: i is positive every time it is compared. Add
   cast to unsigned int.
 * src/nologin.c: Use a main() prototype with no arguments.
 * libmisc/getdate.y: Initialize the type and value fields of the
   terminating entry for each TABLE.
 * libmisc/tz.c: Use "TZ=CST6CDT" as the default timezone.

src/groupmems.c

@@ -126,7 +126,8 @@ static void rmfromgroup (char *user, char **members)
 	}
 
 	while (found && NULL != members[i]) {
-		members[i] = members[++i];
+		members[i] = members[i+1];
+		i++;
 	}
 
 	if (!found) {

src/login.c

@@ -348,6 +348,7 @@ int main (int argc, char **argv)
 	int retcode;
 	pid_t child;
 	char *pam_user;
+	char **ptr_pam_user = &pam_user;
 #else
 	struct spwd *spwd = NULL;
 #endif
@@ -620,7 +621,7 @@ int main (int argc, char **argv)
 			/* if we didn't get a user on the command line,
 			   set it to NULL */
 			pam_get_item (pamh, PAM_USER,
-				      (const void **) &pam_user);
+				      (const void **)ptr_pam_user);
 			if (pam_user[0] == '\0')
 				pam_set_item (pamh, PAM_USER, NULL);
 
@@ -644,7 +645,7 @@ int main (int argc, char **argv)
 			  retcode = pam_authenticate (pamh, 0);
 
 			  pam_get_item (pamh, PAM_USER,
-					(const void **) &pam_user);
+					(const void **) ptr_pam_user);
 
 			  if (pam_user && pam_user[0]) {
 			    pwd = xgetpwnam(pam_user);
@@ -737,7 +738,7 @@ int main (int argc, char **argv)
 		   First get the username that we are actually using, though.
 		 */
 		retcode =
-		    pam_get_item (pamh, PAM_USER, (const void **) &pam_user);
+		    pam_get_item (pamh, PAM_USER, (const void **)ptr_pam_user);
 		setpwent ();
 		pwd = xgetpwnam (pam_user);
 		if (!pwd) {

src/newusers.c

@@ -116,11 +116,11 @@ static int add_group (const char *name, const char *gid, gid_t * ngid)
 	if (gid[0] == '\0') {
 		i = 100;
 		for (pw_rewind (); (pwd = pw_next ());) {
-			if (pwd->pw_uid >= i)
+			if (pwd->pw_uid >= (unsigned int)i)
 				i = pwd->pw_uid + 1;
 		}
 		for (gr_rewind (); (grp = gr_next ());) {
-			if (grp->gr_gid == i) {
+			if (grp->gr_gid == (unsigned int)i) {
 				i = -1;
 				break;
 			}
@@ -133,7 +133,7 @@ static int add_group (const char *name, const char *gid, gid_t * ngid)
 		 */
 		i = atoi (gid);
 		for (gr_rewind (); (grp = gr_next ());)
-			if (grp->gr_gid == i)
+			if (grp->gr_gid == (unsigned int)i)
 				goto add_member;
 	} else
 		/*
@@ -149,7 +149,7 @@ static int add_group (const char *name, const char *gid, gid_t * ngid)
 	 */
 	if (i == -1) {
 		for (i = 100, gr_rewind (); (grp = gr_next ());)
-			if (grp->gr_gid >= i)
+			if (grp->gr_gid >= (unsigned int)i)
 				i = grp->gr_gid + 1;
 	}
 

src/nologin.c

@@ -30,7 +30,7 @@
 #include <unistd.h>
 #include "exitcodes.h"
 
-int main (int argc, char **argv)
+int main ()
 {
 	const char *user, *tty;