lib/std/c: sync "struct stat" for DragonFly

* Add missing functions like ISDIR() or ISREG(). This is required to
  build the zig compiler

* Use octal notation for the S_ constants. This is how it is done for
  ".freebsd" and it is also the notation used by DragonFly in
  "sys/stat.h"

* Reorder S_ constants in the same order as ".freebsd" does. Again, this
  follows the ordering within "sys/stat.h"
035219132bMichael Neumann committed on 9/27/2025, 8:00:40 AMparent19703a5
1 file changedLine totals unavailable