This is very close to this questionthis question, and the same answeranswer applies.
However, in case you’d prefer to edit your project properties in GPS via the Project > Properties dialog:
go to the Switches tab (on the left hand side)
go to the Binder tab (at the top)
tick the Shared GNAT run time checkbox.
While you’re there, tick the Store call stack in exceptions checkbox too; this can help debugging an unhandled exception (the binder switch is -E).