add platform tweaks

login: consider platforms having no domainname field in the utsname struct
include/platform.h: define IUCLC to 0 on platforms where it is not defined

Signed-off-by: Luca Favatella <slackydeb@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

libbb/login.c

@@ -62,10 +62,12 @@ void FAST_FUNC print_login_issue(const char *issue_file, const char *tty)
 			case 'm':
 				outbuf = uts.machine;
 				break;
+#ifndef HAVE_NO_UTSNAME_DOMAINNAME
 			case 'D':
 			case 'o':
 				outbuf = uts.domainname;
 				break;
+#endif
 			case 'd':
 				strftime(buf, sizeof(buf), fmtstr_d, localtime(&t));
 				break;