freebsd.init: set mainProgram (NixOS#371715)

Signed-off-by: John Titor <[email protected]>

Author: rhelmot

pkgs/os-specific/bsd/freebsd/pkgs/init.nix

@@ -1,9 +1,17 @@
-{ mkDerivation, stdenv }:
+{
+  mkDerivation,
+  stdenv,
+  lib,
+}:
 mkDerivation {
   path = "sbin/init";
   extraPaths = [ "sbin/mount" ];
   NO_FSCHG = "yes";
   MK_TESTS = "no";
 
-  meta.broken = !stdenv.hostPlatform.isStatic;
+  meta = {
+    broken = !stdenv.hostPlatform.isStatic;
+    platforms = lib.platforms.freebsd;
+    mainProgram = "init";
+  };
 }