Remove support for DYNIX, IRIX 4, --with-sgi-dl, --with-dl-dld
diff --git a/configure.in b/configure.in
index 412befb..31805c1 100644
--- a/configure.in
+++ b/configure.in
@@ -332,7 +332,7 @@
 
 # Check for unsupported systems
 case $ac_sys_system/$ac_sys_release in
-SunOS/4*|DYNIX/*|IRIX/4*|Linux*/1*)
+SunOS/4*|Linux*/1*)
    echo This system \($ac_sys_system/$ac_sys_release\) is no longer supported.
    echo See README for details.
    exit 1;;
@@ -1246,7 +1246,6 @@
 		fi ;;
 	hp*|HP*) LDSHARED="ld -b";;
 	OSF*) LDSHARED="ld -shared -expect_unresolved \"*\"";;
-	DYNIX/ptx*) LDSHARED="ld -G";;
 	Darwin/1.3*)
 		LDSHARED='$(CC) $(LDFLAGS) -bundle'
 		if test "$enable_framework" ; then
@@ -1443,15 +1442,10 @@
 esac
 
 # Most SVR4 platforms (e.g. Solaris) need -lsocket and -lnsl.
-# However on SGI IRIX 4, these exist but are broken.
 # BeOS' sockets are stashed in libnet.
-case "$ac_sys_system" in
-IRIX*) ;;
-*)
 AC_CHECK_LIB(nsl, t_open, [LIBS="-lnsl $LIBS"]) # SVR4
 AC_CHECK_LIB(socket, socket, [LIBS="-lsocket $LIBS"], [], $LIBS) # SVR4 sockets
-;;
-esac
+
 case "$ac_sys_system" in
 BeOS*)
 AC_CHECK_LIB(net, socket, [LIBS="-lnet $LIBS"], [], $LIBS) # BeOS
@@ -1958,55 +1952,6 @@
 AC_SUBST(DLINCLDIR)
 DLINCLDIR=.
 
-AC_MSG_CHECKING(for --with-sgi-dl)
-AC_ARG_WITH(sgi-dl,
-            AC_HELP_STRING(--with-sgi-dl=DIRECTORY, IRIX 4 dynamic linking),
-[
-AC_MSG_RESULT($withval)
-echo --with-sgi-dl is unsupported, see README
-exit 1
-AC_DEFINE(WITH_SGI_DL, 1,
-  [Define if you want to use SGI (IRIX 4) dynamic linking.
-   This requires the "dl" library by Jack Jansen,
-   ftp://ftp.cwi.nl/pub/dynload/dl-1.6.tar.Z.
-   Do not bother on IRIX 5, it already has dynamic linking using SunOS
-   style shared libraries])
-DYNLOADFILE="dynload_dl.o"
-dldir=$withval
-if test ! -z "$dldir" -a -d "$dldir"
-then LDFLAGS="$LDFLAGS -L$dldir"
-else AC_MSG_ERROR([proper usage is --with-sgi-dl=DIRECTORY])
-fi
-DLINCLDIR=${dldir}
-LIBS="$LIBS -ldl -lmld"], AC_MSG_RESULT(no))
-
-AC_MSG_CHECKING(for --with-dl-dld)
-AC_ARG_WITH(dl-dld,
-            AC_HELP_STRING(--with-dl-dld=DL_DIR, GNU dynamic linking),
-[
-AC_MSG_RESULT($withval)
-echo --with-dl-dld is unsupported, see README
-exit 1
-AC_DEFINE(WITH_DL_DLD, 1, 
-  [Define if you want to emulate SGI (IRIX 4) dynamic linking.
-   This is rumoured to work on VAX (Ultrix), Sun3 (SunOS 3.4),
-   Sequent Symmetry (Dynix), and Atari ST.
-   This requires the 'dl-dld' library,
-   ftp://ftp.cwi.nl/pub/dynload/dl-dld-1.1.tar.Z,
-   as well as the 'GNU dld' library,
-   ftp://ftp.cwi.nl/pub/dynload/dld-3.2.3.tar.Z.
-   Do not bother on SunOS 4 or 5, they already have dynamic linking using
-   shared libraries.])
-DYNLOADFILE="dynload_dl.o"
-dldir=`echo "$withval" | sed 's/,.*//'`
-dlddir=`echo "$withval" | sed 's/.*,//'`
-if test ! -z "$dldir" -a -d "$dldir" -a ! -z "$dlddir" -a -d "$dlddir"
-then LDFLAGS="$LDFLAGS -L$dldir -L$dlddir"
-else AC_MSG_ERROR([proper usage is --with-dl-dld=DL_DIRECTORY,DLD_DIRECTORY])
-fi
-DLINCLDIR=${dldir}
-LIBS="$LIBS -ldl -ldld"], AC_MSG_RESULT(no))
-
 # the dlopen() function means we might want to use dynload_shlib.o. some
 # platforms, such as AIX, have dlopen(), but don't want to use it.
 AC_CHECK_FUNCS(dlopen)