problem with 3.8 release-candidate 1

[Kjetil brinchmann Halvorsen]

This is Lubuntu 3.10 with all updates.
I have compiled the release-candidate 1 from source,
make check goes witout anything special. I have the following script
(save the following under name kjetil_test.m):

%  script to test image functions
V = [1 0 0 0 0 0 1;
     1 0 0 0 0 0 1;
     0 1 0 0 0 1 0;
     0 1 0 0 0 1 0;
     0 0 1 0 1 0 0;
     0 0 0 1 0 0 0;
     0 0 0 1 0 0 0];
VI = int8(V)
class(V)
class(VI)
%  imshow(V, [])
%  imshow(VI,[])
%

Then I do
./run-octave --persist  kjetil_test.m

and when inside the program, I do
imshow(V, [])
  (or, imshow(VI, []) is the same)
--- and then it dies!

The same thing works without problems on a windows machine with
Octave UPM (last released octave)

Exact same problem with octave 4.1+ from todays mercurial repo.

I guess this is some configuration problem I have, what can it be?

Kjetil