It looks like the version of the library that is being used by the WebIDE is out of date?
The problem is in OneWire.h
#define FALSE 0
#define TRUE 1
These should not be there (and looking through github history last year, they were removed, and still is removed in the latest version.)
The version of the library in github is 1.1.0, but the version in the WebIDE is 1.0.0.
Can anyone that’s familiar with the library shed some light on this?