[bug] :eval header argument ignored in the #+call: block

[Leo Alekseyev <dnquark@gmail.com>]

Suppose I have a code block foo, and I want to call it several times
in my org file.  However, foo may be a slow function, and so any time
I evaluate buffer non-interactively (e.g. HTML export) I want to
enable only one out of many calls to :foo

The following doesn't work, but I think it should, since the #+call:
line should run foo with the header argument :eval no-export

#+NAME: foo
#+BEGIN_SRC R :var turn_on_output="FALSE"
if(turn_on_output) { X11() }
#+END_SRC

#+CALL: foo[:eval no-export](turn_on_output="TRUE")  ## this STILL
evaluates on export

Furthermore, a better solution to the situation I described above
might be to set the :eval no-export header argument in the source
block definition, and then over-ride it in the one #+call line that I
want to run during export.  Unfortunately, it doesn't seem that this
is currently possible.

--Leo