support 64bit version of libogg and libvorbis under macosx snow leopard

I've been using the 64 bit versions from quite some time and i have no issues to report. However it would be nice to have the sources compatible with the new architecture

for libogg you just need to remove the line

#include <Carbon/Carbon.h>

from Ogg_Prefix.pch

and in both project you need to set "gcc-4.0" as default compiler. A further step could be to set "build type" to "universal 32/64" but i don't know how this would affect pre 10.6 build systems.