Sun-3 with SunOS
Sun-4 with SunOS

   Works.
   Since Sun has broken their linker again in SunOS 4.1, you must
   specify the full pathnames of the relevant X11 libraries in the top
   level Makefile.

VAX with 4.3BSD or Ultrix

   Works.
   The C compiler can't handle void* correctly, thus GENERIC must be
   defined as char* in the top level Makefile.

Integrated Solutions 680x0 with 4.2BSD or 4.3BSD

   Works, but I haven't tested the X11 interface.
   The C compiler can't handle void* correctly, thus GENERIC must be
   defined as char* in the top level Makefile.

Intel 80386 with System V Release 3 or System V/386 (Interactive)

   Works, but I haven't tested the X11 interface.
   Under Interactive Unix you must not compile with -O.
   Dynamic loading of object files is not supported under System V,
   since the linker doesn't support incremental linking.

IBM RT with AOS

   Zalman Stern <zs01+@andrew.cmu.edu> reported that it works on
   the IBM RT.

Sequent Symmetry

   Richard Kuhns <newton.physics.purdue.edu!sawmill!rjk> and
   On G. Paradise <oparadis@erseq.oracle.com> reported that Elk works
   on the Sequent.

HP 9000 Series 300
 
   Works.
   The X11 extension works with MIT's X11 Release 4.
   Before calling "make", set your SHELL environment variable to /bin/sh.
   The "ALIGN redefined" warnings of the C compiler can be ignored.

HP 9000 Series 800

   Works.
   The X11 extension works with MIT's X11 Release 4.
   Before calling "make", set your SHELL environment variable to /bin/sh.
   Dynamic loading of object files doesn't work due to a bug in HP's
   linker.  The bug will probably be fixed in the next release of HP-UX.
   C compiler messages like "Subspace characteristics may not be changed
   after first definition" can be ignored.

Sony NEWS 1750/1850 (68k)

   Works.

DECStation 3100
Sony NEWS 3860
(and probably other MIPS-based machines)

   MIPS-based machines don't seem to have an alloca() that can be used
   with Elk.  Thus you must either install the portable version or
   use the GNU C-compiler (gcc).

   In addition, you must link the executable in a way that the data
   segment starts at 0x800000 (this number must correspond to the value
   of POINTER_CONSTANT_HIGH_BITS in src/config.h).  This can be achieved
   by the cc-option -Wl,-D,800000.

   There are a couple of problems with the current release of gcc on
   MIPS-based machines:  
   
      o gcc doesn't correctly compile files that use varargs.  Thus, the
        files src/error.c and src/print.c must be compiled with cc

      o it doesn't recognize -Wl,-D,80000.  Thus, Elk must be linked with cc

      o on the DECStation 3100, it barfs over src/bignum.c (this is a bug
	in gcc).  You must gcc -S bignum.c, edit bignum.s and replace the
	symbol Infinity by 1e308, and then gcc -c bignum.s

   Thus, until the problems with gcc are fixed or a real alloca() is
   provided by MIPS, I recommend the following:

      cd src
      [gcc -S bignum.c; vi bignum.s; gcc -c bignum.s on the DECStation]
      cc -c error.c; cc -c print.c
      cd ..
      make TARGETS=src CC=gcc
      rm src/scheme; make TARGETS=src
      make CC=gcc

   Incremental linking currently doesn't work on MIPS-based machines.
   /bin/ld complains about "gp relocation out-of-range errors"; so far
   nobody could tell me what exactly this means.

   Thus I recommend to remove CAN_LOAD_OBJ from src/config.h and add
   #define INIT_OBJECTS.  You can then create a statically linked
   interpreter with your extensions by means of the shell script
   src/link-scheme.  For instance, to create an interpreter with the
   X11 extensions, call

      cd src
      link-scheme xscheme ../lib/unix.o ../lib/{xlib,xt,xaw}/*.o
	-lXaw -lXext -lXmu -lXt -lX11


X11 Release 3

   The current release of the X11 extension of Elk has been tested
   under X11 Release 3 and X11 Release 4.
   If you are still using X11R3, copy the file lib/xaw/ascii.d.x11r3
   to lib/xaw/ascii.d, remove the file lib/xaw/toggle.d, and remove
   all occurrences of "toggle" from the Makefile in lib/xaw (there is
   no toggle widget in X11R3).

Interface to the OSF/Motif widgets

   The Motif extension assumes that the Motif include files are in of
   /usr/include/Xmotif/Xm (and /usr/include/Xmotif/X11 for Motif 1.0).
   If the directory isn't called Xmotif on your system, edit
   lib/motif/Makefile and lib/motif/xt/Makefile and replace Xmotif by
   the correct name.

   The Motif extension assumes that you have installed Motif 1.1.
   If you are using Motif 1.0, go to lib/motif/xt and copy
   Makefile-1.0 to Makefile.  In addition, edit scm/xwidgets,
   go to the line with -lXm in it and replace -lXt by the name
   of Motif's Xt library on your system, e.g. -lXtm.  Edit the
   line starting with MOTIFXT= in the top level Makefile accordingly
   (note that Motif 1.0 uses its own version of Xt).
