jhbuild fails to work

[Joel Feiner]

I can no longer use jhbuild to build the tree because it complains of
missing modules.  It was working as of last week, but something changed
since then (don't know what) and now I get a message like this every
time I try to build anything with it:

jhbuild build: dependent module "xorg-fonts" not found
Usage: jhbuild [ -f config ] command [ options ... ]

The module is sometimes different (for the xserver, for example, I got
libXxf86fixes).

I svn up'ed the jhbuild source and reinstalled it.  No luck.  Any ideas
what could be going wrong here?