Clarifications on fork family syscalls - no longer in process.c?

Hello all, I was working on the 2.6 kernel (2.6.37) and I have just downloaded the 3.13 Linux release and noticed that sys_fork(), sys_vfork(), sys_clone() are no longer defined in <arch>/kernel/process.c I have done some searches into the kernel and through the changelogs of the different versions, but was not able to conclude where the fork syscalls are.. and if they still exist.. Has the fork procedure changed? When the changes have been done (since which version)? Thanks a lot for the clarifications. Regards