re-instate old macros to keep older gdb/binutils building in unisrc.

        Back out this patch part:
        2014-01-21  Tom Tromey  <tromey@redhat.com>
          * ansidecl.h (ANSI_PROTOTYPES, PTRCONST, LONG_DOUBLE, PARAMS)
          (VPARAMS, VA_START, VA_OPEN, VA_CLOSE, VA_FIXEDARG, CONST)
          (VOLATILE, SIGNED, PROTO, EXFUN, DEFUN, DEFUN_VOID, AND, DOTS)
          (NOARGS): Don't define.