diff --git a/lib/config-riscos.h b/lib/config-riscos.h
index 9f585565d8..879be03d52 100644
--- a/lib/config-riscos.h
+++ b/lib/config-riscos.h
@@ -36,36 +36,15 @@
 /* Define if you want the built-in manual */
 #define USE_MANUAL
 
-/* Define if you have the gethostbyname_r() function with 3 arguments */
-#undef HAVE_GETHOSTBYNAME_R_3
-
-/* Define if you have the gethostbyname_r() function with 5 arguments */
-#undef HAVE_GETHOSTBYNAME_R_5
-
-/* Define if you have the gethostbyname_r() function with 6 arguments */
-#undef HAVE_GETHOSTBYNAME_R_6
-
-/* Define if you need the _REENTRANT define for some functions */
-#undef NEED_REENTRANT
-
-/* Define if you want to enable IPv6 support */
-#undef USE_IPV6
-
 /* Define if struct sockaddr_in6 has the sin6_scope_id member */
 #define HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID 1
 
-/* Define this to 'int' if ssize_t is not an available typedefed type */
-#undef ssize_t
-
 /* Define if you have the alarm function. */
 #define HAVE_ALARM
 
 /* Define if you have the <arpa/inet.h> header file. */
 #define HAVE_ARPA_INET_H
 
-/* Define if you have the `closesocket' function. */
-#undef HAVE_CLOSESOCKET
-
 /* Define if you have the <fcntl.h> header file. */
 #define HAVE_FCNTL_H
 
@@ -75,30 +54,15 @@
 /* Define if getaddrinfo exists and works */
 #define HAVE_GETADDRINFO
 
-/* Define if you have the `geteuid' function. */
-#undef HAVE_GETEUID
-
-/* Define if you have the `gethostbyname_r' function. */
-#undef HAVE_GETHOSTBYNAME_R
-
 /* Define if you have the `gethostname' function. */
 #define HAVE_GETHOSTNAME
 
-/* Define if you have the `getpass_r' function. */
-#undef HAVE_GETPASS_R
-
-/* Define if you have the `getpwuid' function. */
-#undef HAVE_GETPWUID
-
 /* Define if you have the `gettimeofday' function. */
 #define HAVE_GETTIMEOFDAY
 
 /* Define if you have the `timeval' struct. */
 #define HAVE_STRUCT_TIMEVAL
 
-/* Define if you have the <io.h> header file. */
-#undef HAVE_IO_H
-
 /* Define if you have the <netdb.h> header file. */
 #define HAVE_NETDB_H
 
@@ -108,51 +72,24 @@
 /* Define if you have the <net/if.h> header file. */
 #define HAVE_NET_IF_H
 
-/* Define if you have the <pwd.h> header file. */
-#undef HAVE_PWD_H
-
 /* Define if you have the `select' function. */
 #define HAVE_SELECT
 
-/* Define if you have the `sigaction' function. */
-#undef HAVE_SIGACTION
-
 /* Define if you have the `signal' function. */
 #define HAVE_SIGNAL
 
 /* Define if you have the `socket' function. */
 #define HAVE_SOCKET
 
-/* Define if you have the `strcasecmp' function. */
-#undef HAVE_STRCASECMP
-
-/* Define if you have the `strcmpi' function. */
-#undef HAVE_STRCMPI
-
 /* Define if you have the `stricmp' function. */
 #define HAVE_STRICMP
 
-/* Define if you have the <strings.h> header file. */
-#undef HAVE_STRINGS_H
-
-/* Define if you have the <sys/param.h> header file. */
-#undef HAVE_SYS_PARAM_H
-
-/* Define if you have the <sys/select.h> header file. */
-#undef HAVE_SYS_SELECT_H
-
-/* Define if you have the <sys/sockio.h> header file. */
-#undef HAVE_SYS_SOCKIO_H
-
 /* Define if you have the <sys/types.h> header file. */
 #define HAVE_SYS_TYPES_H
 
 /* Define if you have the <termios.h> header file. */
 #define HAVE_TERMIOS_H
 
-/* Define if you have the <termio.h> header file. */
-#undef HAVE_TERMIO_H
-
 /* Define if you have the <unistd.h> header file. */
 #define HAVE_UNISTD_H
 
@@ -162,24 +99,6 @@
 /* The size of `size_t', as computed by sizeof. */
 #define SIZEOF_SIZE_T 4
 
-/* Define if you have the ANSI C header files. */
-#undef STDC_HEADERS
-
-/* Version number of package */
-#undef VERSION
-
-/* Number of bits in a file offset, on hosts where this is settable. */
-#undef _FILE_OFFSET_BITS
-
-/* Define to empty if `const' does not conform to ANSI C. */
-#undef const
-
-/* Define to `unsigned' if <sys/types.h> does not define. */
-#undef size_t
-
-/* Define to `int' if <sys/types.h> does not define. */
-#undef ssize_t
-
 /* Define if you have a working ioctl FIONBIO function. */
 #define HAVE_IOCTL_FIONBIO