Trouble installing on MacOS

[PatrickMcClatchy]

Hi, hopefully someone can help.

remotes::install_github('tiagodc/TreeLS') 

gives me:

Error: Failed to install 'TreeLS' from GitHub: Failed to R CMD build package, try build = FALSE. and

remotes::install_github('tiagodc/TreeLS', build = FALSE)

doesn't work either. Xcode is installed.

Regards,

Patrick