Can you build both PC and iPhone?

There is a source using iPhoneKeyboard, but uses PC use and both for iPhone.

Because it is troublesome to change a source one by one, both want to go in the same source,

but an error appears in a part of iPhoneKeyboard when I build with a PC.

When I build with a PC, I want to build in defiance of the above, but is there a method?

By the way, if it is C++

 #ifdef XXX
 #endif

By the above, I can take it off.

How will you do it in Unity?

It may be a rudimentary question, but thank you