You need empty definitions for the preprocessor symbols FAR and far - for example "Project Options" -> "Compiler" Tab, "Define preprocessor symbols" field, add the names FAR and far.
I was kind of hoping this 16-bit Windows stuff was gone by now, some 20 years later, but apparently not. Oh well, I will add some FAR/far/NEAR/near definitions for the next upload.
Also, for now, comment out line 10 in MoonTool.rc: #include "moontool.h". This include adds nothing, but will trigger errors about bad compiler version for <time.h>, <stdio.h> etc. Such include files are meaningless for a resource script, but I should handle this better when they are. I will try to fix this for the next upload.