check_fokirtor.sh - replaced gdb wrapper "gcore" with gdb 

My distribution doesn't have the gcore script debian wheezy has. In order to get your script working on my machines, I just replaced the gcore call with the respective gdb call which I found in the gcore script.

It's is now working on current arch linux systems (x86, x86_64, armv6h) and still on debian, of course.