pkg/csource: add ability to annotate syscalls using comments in C reproducers

Providing additional info, especially regarding syscall arguments, in reproducers
can be helpful. An example is device numbers passed to mknod(2).

This commit introduces an optional annotate function on a per target basis.

Example for the OpenBSD target:

  $ cat prog.in
  mknod(0x0, 0x0, 0x4503)
  getpid()
  $ syz-prog2c -prog prog.in
  int main(void)
  {
    syscall(SYS_mmap, 0x20000000, 0x1000000, 3, 0x1012, -1, 0, 0);
    syscall(SYS_mknod, 0, 0, 0x4503); /* major = 69, minor = 3 */
    syscall(SYS_getpid);
    return 0;
  }

0 files changed, 0 insertions, 0 deletions