Seems that it did, indeed, compile! However when I start ROOT I get the following message several times before I finally get the prompt.
Error: cannot open c:\CYGWIN\C\ROOT\cint/MAKEINFO
!!! There are examples of MAKEINFO files under c:\CYGWIN\C\ROOT\cint/platform/ !
The MAKEINFO file is in the directory in question but maybe there’s a problemn in the way ROOT looks for it as one can see the pth has both backslashews and forward slashes. I do have %ROOTSYS% set and also the PATH variable.