[fpc-pascal]disable CTRL-C in readkey

[Jose Pascual]

Hi,

I have a program which use keypressed and readkey (crt unit) in linux.
When I press CTRL-C
readkey return #3. It's okey and working but I like to disable this
option in keyboard subsystem
because I want to use my only CTRL-C function. 

I have implemented my function for signal SIGINT but I think keyboard
subsystem is caching this
signal and it doesn't reach to the my function.

best regards