*: remove a few more cases of argc usage. -89 bytes.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

coreutils/chroot.c

@@ -12,18 +12,16 @@
 #include "libbb.h"
 
 int chroot_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int chroot_main(int argc, char **argv)
+int chroot_main(int argc UNUSED_PARAM, char **argv)
 {
-	if (argc < 2) {
-		bb_show_usage();
-	}
-
 	++argv;
+	if (!*argv)
+		bb_show_usage();
 	xchroot(*argv);
 	xchdir("/");
 
 	++argv;
-	if (argc == 2) {
+	if (!*argv) { /* no 2nd param (PROG), use shell */
 		argv -= 2;
 		argv[0] = getenv("SHELL");
 		if (!argv[0]) {