i386-unknown-isc3.0 as your configuration name.
Use i386-*-esix for Esix; Emacs runs as of version 19.6.
Use i386-*-linux-gnu for GNU/Linux systems; Emacs runs as of version 19.26.
- Use i386-*-cygwin for Cygwin; Emacs builds as of version 21.4, in both X11
+ Use i386-*-cygwin for Cygwin; Emacs builds as of version 22.1, in both X11
and non-X11 modes. (The Cygwin site has source and binaries for 21.2.)
Use i386-intsys-sysv for Integrated Solutions 386 machines.
It may also be correct for Microport systems.