1763. [bug] fdupont
Changed the way hook libraries are unloaded. Now unload is done
in two phases: the first phase calls unload() entry points and
- removed callouts, the second phase unmaps hook library memory
+ removes callouts, the second phase unmaps hook library memory
spaces. This should lead to less problems including less crashes
at exit time. On the other hand, incorrect libraries can stay
in memory until exit and prevent any (re)load.