TB 6.0a5: updater doesn't work on Linux (cannot find libraries)

When testing the 6.0a5 updater using our own Linux64 build, the updater fails to run because it cannot locate Mozilla shared libraries:

error while loading shared libraries: libmozsqlite3.so: cannot open shared object file: No such file or directory

Code in toolkit/xre/nsUpdateDriver.cpp is supposed to add the Browser directory to LD_LIBRARY_PATH. We will need to see why that is not happening.