Please copy the source archive for the Mozilla sources into this directory.
At the moment "seamonkey-1.1.12-source.tar.gz" is required, it can be found
here:
 http://releases.mozilla.org/pub/mozilla.org/seamonkey/releases/1.1.13

Windows builders need also
  "vc8-moztools.zip"
which can be found here:
  ftp://ftp.mozilla.org/pub/mozilla.org/mozilla/libraries/win32/historic/vc8/
