Created by: zhuomao123
…ompatibility
Implement multiple POSIX-compliant system calls to improve LTP test compatibility:
- Process group management: setpgid, getpgid, setsid, getsid
- Signal handling: tkill, tgkill
- Resource management: prlimit64, getrusage
- System info: sysinfo, getrandom
- File sync: fdatasync, wait4
Also fix FAT32 long filename support in directory listing and clean up duplicate syscall constant definitions.