To make it worse, I tried to compare that with xgap on a SUN and couldn't
compile it. It ends with
cc -L/usr/openwin/lib -o xgap xcmds.o utils.o gapgraph.o gaptext.o pty.o
popdial.o main.o -lXmu -lXaw -lXt -lXext -lX11 -lm
ld: Undefined symbol
*** Error code 2
XGAP really requires X11R5 (or 6), at least to compile. If you try to compile
it using either X11R4 or OpenWin you *might* end up with some undefined
symbols or possible with a version that is useless, as it starts
flickering the cursor once every millisecond, because of some bug
in the older X Versions. However, once compiled using X11R5 it should run
under X11R4 or OpenWindows, there is a precompiled version on
"ftp.math.rwth-aachen.de" in the directory "pub/gap/bin" for Suns.
However, there is still another problem, some older version of
GCC on Suns seem to have a problem with 'ioctl' so if in case one has
the X11R5 library it is better to compile XGAP using the native CC.
As for the Linux version: I don't have any access to a linux machine,
but I was told that someone has compiled XGAP on such a machine, I
will try to find out more details about it.