Warning for xulrunner 1.9.1 users

[Mike Hommey]

Beware ! xulrunner 1.9.1 might break some applications like epiphany, galeon,
yelp, chmsee, etc.

You have three main options to work around this problem:

    * Set the MOZ_GRE_CONF environment variable to /etc/gre.d/1.9.system.conf
    * Remove the /etc/gre.d/1.9.1.system.conf file
    * Copy the /etc/gre.d/1.9.system.conf file in the ${HOME}/.gre.d
      directory (which you can create if it doesn’t exist, which is very
      likely)

For the moment, I identified a definite break in epiphany. Depending on what
API the applications use, they might break more or less. What happens is that
some of the applications depending on xulrunner-1.9, using the XPCOM
standalone glue, give a too broad range of versions of xulrunner they claim
to be compatible with. The net result is that the glue can end up loading
libxul 1.9.1, which may not be totally binary compatible with what the
application actually needs.

The problem may or may not happen on your computer, because the XPCOM glue
is half broken in its way to find a proper libxul : it stops at the first
one if finds that fits in the given range. This means that depending on the
order of the files in the /etc/gre.d directory, you can get a different
version of libxul.

The workarounds above ensure libxul 1.9 is always loaded.

Mike