Teriiehina.net

In a nutshell, this is a problem with OSX itself.

Apple chose to ship Leopard with an emulated libreadline package.
But the emulation is incomplete, and programs that link against it expecting
a “real” libreadline fail with erros like the ones you quote.
I suggest complaining to Apple. They should hear from their users that
their choice of libraries was not good.
Meanwhile, your options are either
(1) delete the broken libreadline that shipped with Leopard
and replace it with the real gnu libreadline
(2) tell gnuplot not to use libreadline at all
./configure –with-readline=builtin

Ca m’a fait perdre 2h … génial … merci Apple