DragonflyBSD: add ENOMEDIUM and EASYNC

These errno's are defined in <sys/errno.h> on DragonFlyBSD.

Signed-off-by: Levente Kurusa <lkurusa@acm.org>

src/unix/bsd/freebsdlike/dragonfly/mod.rs

@@ -222,6 +222,8 @@ pub const O_DIRECTORY: ::c_int = 0x08000000;
 pub const F_GETLK: ::c_int = 7;
 pub const F_SETLK: ::c_int = 8;
 pub const F_SETLKW: ::c_int = 9;
+pub const ENOMEDIUM: ::c_int = 93;
+pub const EASYNC: ::c_int = 99;
 pub const ELAST: ::c_int = 99;
 pub const RLIMIT_POSIXLOCKS: ::c_int = 11;
 pub const RLIM_NLIMITS: ::rlim_t = 12;