Can 来 be used as a 虚词?
ABC calls this a 连词, which they explain like this:

Conjunction
Liáncí 连词
A conjunction is a word that joins phrases or sentences together to form a larger sentence or chunk of thought. Some examples include érqiě 'furthermore', suīrán 'although', suǒyǐ 'therefore', jiù 'then' and yàoburán 'otherwise'.

here's ABC's relative entry for 来:

CONJ.(in order) to
唱个歌儿来凑热闹
chàng ge gēr lái còu rènao
sing a song to liven things

Here's some other examples from the A Chinese English Dictionary:

7 (used between a verbal expression and a verb or between two verbal expressions) in order to
大家想办法来解决。
Dàjiā xiǎng bànfǎ lái jiějué.
Let's think of a way to solve the problem.
我们得尽一切力量来完成计划。
Wǒmen děi jìn yīqiè lìliang lái wánchéng jìhuà.
We must do all we can to implement the plan.
你又能用什么理由来说服他呢？
Nǐ yòu néng yòng shénme lǐyóu lái shuōfú tā ne？
And what arguments can you use to convince him?