* renamed syscalls _kern_[gs]et_tzfilename
to _kern_[gs]et_real_time_clock_is_gmt, as the filename part is no longer
relevant (and the two corresponding parameters were removed)
* C++-ified and reworked clockconfig to use the info from 'Time settings'
to setup the timezone info during boot
* removed invocation of _kern_get_tzfilename() from tzset(), as the syscall
no longer exists and tzset() is currently broken anyway
* adjusted the Time preflet to use the renamed syscall when getting/setting
the RTC info
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37881 a95241bf-73f2-0310-859d-f6bbb57e9c96