krb5: fix build on FreeBSD

Failed with:

```
packet.c:481:16: error: use of undeclared identifier 'ENODATA'
  481 |         return ENODATA;
      |                ^
1 error generated.
```

Fixed by applying a patch from FreeBSD ports.

pkgs/development/libraries/kerberos/krb5.nix

@@ -2,6 +2,7 @@
   lib,
   stdenv,
   fetchurl,
+  fetchpatch,
   bootstrap_cmds,
   byacc, # can also use bison, but byacc has fewer dependencies
   keyutils,
@@ -42,6 +43,15 @@ stdenv.mkDerivation rec {
     hash = "sha256-GogyuMrZI+u/E5T2fi789B46SfRgKFpm41reyPoAU68=";
   };
 
+  patches = lib.optionals stdenv.hostPlatform.isFreeBSD [
+    (fetchpatch {
+      name = "fix-missing-ENODATA.patch";
+      url = "https://cgit.freebsd.org/ports/plain/security/krb5-122/files/patch-lib_krad_packet.c?id=0501f716c4aff7880fde56e42d641ef504593b7d";
+      extraPrefix = "";
+      hash = "sha256-l8ev+WrDKbTqwgBRYhfJGELkCCE8mJTqVHFBvvCPvgE=";
+    })
+  ];
+
   outputs = [
     "out"
     "lib"