extern int printf (const char *, ...);extern void target(void);extern void alias_for_target(void);extern void asm_for_target(void);extern int g_int, alias_int; void inunit2(void); void inunit2(void){  printf("in unit2:\n");  target();  alias_for_target();  /* This symbol is not supposed to be available in this unit:     asm_for_target();   */  printf("g_int = %d\nalias_int = %d\n", g_int, alias_int);}