diff --git a/acconfig.h b/acconfig.h
index 76b65792d..60556e880 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -14,38 +14,23 @@
 #undef HAVE_U_INT32_T
 #undef HAVE_U_INT64_T
 
-#undef HAVE_FOUR_VALUED_KRB_PUT_INT
-
 #ifdef HAVE_FOUR_VALUED_KRB_PUT_INT
 #define KRB_PUT_INT(F, T, L, S) krb_put_int((F), (T), (L), (S))
 #else
 #define KRB_PUT_INT(F, T, L, S) krb_put_int((F), (T), (L))
 #endif
 
-/*  Define this if you have a IPv6 */
-#undef HAVE_IPV6
-
-/* define if getcwd() is broken (such as in SunOS) */
-#undef BROKEN_GETCWD
-
-/* Define to isoc_realloc if you have a broken realloc */
-#undef BROKEN_REALLOC
 #ifdef BROKEN_REALLOC
 #define realloc(X, Y) isoc_realloc((X), (Y))
 #define isoc_realloc(X, Y) ((X) ? realloc((X), (Y)) : malloc(Y))
 #endif
 
-#undef VOID_RETSIGTYPE
-
 #ifdef VOID_RETSIGTYPE
 #define SIGRETURN(x) return
 #else
 #define SIGRETURN(x) return (RETSIGTYPE)(x)
 #endif
 
-/* Define if you have a readline compatible library */
-#undef HAVE_READLINE
-
 #define RCSID(msg) \
 static /**/const char *const rcsid[] = { (char *)rcsid, "\100(#)" msg }
 
@@ -59,8 +44,6 @@ static /**/const char *const rcsid[] = { (char *)rcsid, "\100(#)" msg }
 #define SGTTY
 #endif
 
-/* telnet stuff ----------------------------------------------- */
-
 /*
  * Define NDBM if you are using the 4.3 ndbm library (which is part of
  * libc).  If not defined, 4.2 dbm will be assumed.
@@ -69,59 +52,22 @@ static /**/const char *const rcsid[] = { (char *)rcsid, "\100(#)" msg }
 #define NDBM
 #endif
 
-/* define this for OTP support */
-#undef OTP
-
-/* define this if you want to use the KDC as a kaserver */
-#undef KASERVER
-
-/* define this if you want support for reading kaserver databases in hprop */
-#undef KASERVER_DB
-
-/* define this if you have kerberos 5 */
-#undef KRB5
-
-/* define this if you want encryption */
-#undef ENCRYPTION
-
-/* define this if you want authentication */
-#undef AUTHENTICATION
+/* telnet stuff ----------------------------------------------- */
 
 #if defined(ENCRYPTION) && !defined(AUTHENTICATION)
 #define AUTHENTICATION 1
 #endif
 
-/* define if you want key-deriving des3 code */
-#undef NEW_DES3_CODE
-
-/* Set this if you want des encryption */
-#undef DES_ENCRYPTION
-
 /* Set this to the default system lead string for telnetd 
  * can contain %-escapes: %s=sysname, %m=machine, %r=os-release
  * %v=os-version, %t=tty, %h=hostname, %d=date and time
  */
 #undef USE_IM
 
-/* define this if you want diagnostics in telnetd */
-#undef DIAGNOSTICS
-
-/* define this if you want support for broken ENV_{VALUE,VAR} systems  */
-#undef ENV_HACK
-
-/*  */
-#undef OLD_ENVIRON
-
 /* Used with login -p */
 #undef LOGIN_ARGS
 
-/* Define if there are working stream ptys */
-#undef STREAMSPTY
-
 /* set this to a sensible login */
 #ifndef LOGIN_PATH
 #define LOGIN_PATH BINDIR "/login"
 #endif
-
-/* operating system kludges ahead */
-#undef SunOS