Linux: Enhance glibcsyscalls.h to support listing system calls

Linux: Enhance glibcsyscalls.h to support listing system calls

The script can now be called to query the definition status of
system call numbers across all architectures, like this:

$ python3 sysdeps/unix/sysv/linux/glibcsyscalls.py query-syscall sync_file_range sync_file_range2
sync_file_range:
  defined: aarch64 alpha csky hppa i386 ia64 m68k microblaze mips/mips32 mips/mips64/n32 mips/mips64/n64 nios2 riscv/rv64 s390/s390-32 s390/s390-64 sh sparc/sparc32 sparc/sparc64 x86_64/64 x86_64/x32
  undefined: arm powerpc/powerpc32 powerpc/powerpc64
sync_file_range2:
  defined: arm powerpc/powerpc32 powerpc/powerpc64
  undefined: aarch64 alpha csky hppa i386 ia64 m68k microblaze mips/mips32 mips/mips64/n32 mips/mips64/n64 nios2 riscv/rv64 s390/s390-32 s390/s390-64 sh sparc/sparc32 sparc/sparc64 x86_64/64 x86_64/x32