Using pymake to build mozilla on Windows

A number of people, myself included, have had trouble getting pymake to build Mozilla on Windows. Roc discovered the trick to getting it to work: use relative paths in the mozconfig. For example, my mozconfig (which lives in $srcdir/mozconfig) for a debug build is:

. $topsrcdir/browser/config/mozconfig
mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/objdir
ac_add_options --enable-debug
ac_add_options --disable-optimize
ac_add_options --enable-tests

I then build with the commands:

cd $srcdir/objdir
export SHELL; time python -O ../build/pymake/make.py -f ../client.mk -j4

It takes about 26 minutes to build on my Core i7  M620. A normal build is about 50 minutes.