install profiler hooks only if profiling is desired
install profiler hooks only if profiling is desired

Collecting statistics can be somewhat expensive so avoid any slowdowns
if no one is interested in results anyway.

http://bugzilla.gnome.org/show_bug.cgi?id=572258

joeshaw/gjs,pixunil/cjs,magcius/gjs,pixunil/cjs,djdeath/gjs,endlessm/gjs,pixunil/cjs,djdeath/gjs,joeshaw/gjs,mtwebster/cjs,endlessm/gjs,endlessm/gjs,djdeath/gjs,magcius/gjs,magcius/gjs,pixunil/cjs,joeshaw/gjs,joeshaw/gjs,mtwebster/cjs,endlessm/gjs,magcius/gjs,djdeath/gjs,magcius/gjs,pixunil/cjs,mtwebster/cjs,mtwebster/cjs,joeshaw/gjs,djdeath/gjs,mtwebster/cjs,endlessm/gjs