dovecot: use libxcrypt on Linux

Formula/dovecot.rb

@@ -4,6 +4,7 @@ class Dovecot < Formula
   url "https://dovecot.org/releases/2.3/dovecot-2.3.19.tar.gz"
   sha256 "0173f693d441b6248b8a62aa5fd690021a1f04a12902653e0bf2e5b012fe437b"
   license all_of: ["BSD-3-Clause", "LGPL-2.1-or-later", "MIT", "Unicode-DFS-2016", :public_domain]
+  revision 1
 
   livecheck do
     url "https://www.dovecot.org/download/"
@@ -22,6 +23,7 @@ class Dovecot < Formula
   depends_on "openssl@1.1"
 
   uses_from_macos "bzip2"
+  uses_from_macos "libxcrypt"
   uses_from_macos "sqlite"
 
   on_linux do