Default mount mode on cygwin is text. Original B19 gdb fails to attach to a running process. I've fixed the problem in this binary . If you run cygnus tools remotely via telnet or ssh, you may find X Window version of gdb very usefull. New b-19 specific patch for MIT X11R6.3 release .
Precompiled binaries are also available.
B-20 specific patch for Open Group X11R6.4 release . See compilation instructions at the beginning of the diff. If you have no enough disk space to compile X11, download precompiled binaries . The login and rexecd programs are for NT only. If you want to compile rxvt yourself, download the sources , and apply this patch.