Deactivate MALLOC_CHECK_ on x86_64

[Alex Fiestas]

Hi
Seems that MALLOC_CHECK_ feature of glibc is kind of broken in x86_64, giving 
false positives. In release mode this has no effect to the user, just when 
you're running KDE in development mode, MALLOC_CHECK_ will be set at 2, which 
means that malloc will abort the application when one of that false given 
errors happen.

So I suggest to deactivate MALLOC_CHECK_ on 64 bits systems, at least until it 
gets fixed.

Some applications that usually crash on my system are:
- digikam (I'm in digikam sprint right now and I've asked gilles and he 
agrees)
- kdevelop (I'm with apol here and he's concerned about this issue too).

Everybody agrees with that? 

*http://techbase.kde.org/Development/malloc_check

-------
Alex Fiestas
Blog: http://www.afiestas.org
Jabber: afiestaso at gmail.com
Irc: afiestas -- irc.freenode.net
Email: alex {at} eyeos.org