The session extension ensures now that get_session_var can rely

The session extension ensures now that get_session_var can rely
on the state of $_SESSION/$HTTP_SESSION_VARS. It does not look up
symbols in the global symbol table anymore.

This was achieved by actually planting references between every
$_SESSION["x"] and $x, not only when restoring a session, but also
when registering a session variable (in a register_globals=1 context).

Upon registering a new variable, this memory leak continues to show
up, regardless of register_globals.

ext/session/session.c(272) :  Freeing 0x0818F01C (12 bytes), script=test

Obviously, the newly allocated empty zval is not properly freed.  If anyone
has any idea on how to fix that, please step forward.