fix: warnings for 'c-run-time.c'

Creates different arities for DFLN.

typedef dylan_value (*DLFN0)(void);
typedef dylan_value (*DLFN1)(dylan_value);
typedef dylan_value (*DLFN2)(dylan_value, dylan_value);
... etc

Changing DLFN to a union

typedef union {
  void* raw;
  DLFN0 mep0;
  DLFN1 mep1;
  DLFN2 mep2;
  DLFN3 mep3;
  DLFN4 mep4;
  DLFN5 mep5;
  DLFN6 mep6;
  DLFN7 mep7;
  DLFN8 mep8;
  DLFN9 mep9;
  DLFN10 mep10;
  DLFN64 mep64;
} DLFN;

Then rewrite the call logic using the correct
type per arity.

switch (teb->argument_count) {
  case 0: return (mep.mep0)();
  case 1: return (mep.mep1)(v[0]);
  ...

Closes #1650

Author: fraya