[Patch, Fortran] PR fortran/35681: First part, fix ELEMENTAL dependency handling for MVBITS

[Dominique Dhumieres]

The only comment I can make now is that the patch conflicts with the patch
in http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36091#c1

I am trying to fix the mess in my tree.

Dominique