[Bug jit/84288] Support jit on Solaris

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84288

--- Comment #6 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
I'm not sure if r258388 fixes the linker issue on Solaris, but it should make
it much easier to fix; e.g. to apply your patch here:
  https://gcc.gnu.org/ml/gcc-patches/2018-02/msg00835.html
(currently reported as untested)