I am getting the following error:
$ gmake -f client.mk build
/usr/bin/gmake -f /mozilla/client.mk build
gmake[1]: Entering directory `/c/cygwin/mozilla'
gmake[1]: /mozilla/client.mk: No such file or directory
gmake[1]: *** No rule to make target `/mozilla/client.mk'.  Stop.
gmake[1]: Leaving directory `/c/cygwin/mozilla'
gmake: *** [build] Error 2

I am using the directory c:\cygwin\mozilla\calendar\sunbird

CVSROOT=:pserver:anonymous@cvs-mirror.mozilla.org:/cvsroot
CVS_RSH=/bin/ssh
MOZ_BITS=32
MOZ_DEBUG=1
MOZ_SRC=mozilla
MOZ_TOOLS='C:\moztools'
TOPSRCDIR=/mozilla

I am using Visual Studio 6.0, GNU Make version 3.79.1, the latest cygwin and 
gnu automake (from about a week or two ago, automake (GNU automake) 1.9.6).

I have a .mozconfig in /mozilla:
$ more .mozconfig
. $topsrcdir/calendar/sunbird/config/.mozconfig

And a .mozconfig in /mozilla/calendar/sunbird/config:
$ more .mozconfig
# This file specifies the build flags for Sunbird.  You can use it by 
adding:
#  . $topsrcdir/calendar/sunbird/config/mozconfig
# to the top of your mozconfig file.

mk_add_options MOZ_CO_PROJECT=calendar
ac_add_options --enable-application=calendar

It looks like I have a path dorked up, but I can't imagine where.  Any help 
would be great.