ucalls -S option does not work with newer kernels

When experimenting with ucalls I discovered the -S (--syscalls) option does not work with newer Linux kernels. The code has a regular expression to find the functions to instrument:

syscall_regex = "^[Ss]y[Ss]_.*"

This is not going to match the syscall function names for newer kernels. Wouldn't it be more efficient to implement the syscall instrumentation using the raw_syscalls:sys_enter and raw_syscalls:sys_exit tracepoints and map the syscall number like syscount.py does?

Start with the ucalls implementation for the -S/--syscalls option and compare it with syscount.py, especially how syscall numbers are mapped. Check the existing syscall regex and tracepoint-related paths, then verify that syscall instrumentation works on newer Linux kernels using raw_syscalls:sys_enter and raw_syscalls:sys_exit.

Written by the indexing model from the issue text.