- tentatively activate PCH if gcc > 3.4. remove XP_ defines (which were
undocumented; now in scripting/spidermonkey.h)
- rename some config defines
- move sysdep/debug.h to lib/debug.h (it's portable; was wrong all
along)
- grouped all debug heap related stuff to debug.h:debug_heap_*
- sysdep: fix circular include issue with debug.h
This was SVN commit r2427.
