dbus: fix build on Darwin (#484428)

pkgs/by-name/db/dbus/implement-getgrouplist.patch

@@ -95,14 +95,15 @@ Without it, only the user's primary group is used in authentication!
 +}
 --- dbus-1.6.8/dbus/dbus-sysdeps-unix.c.orig	2013-02-28 13:08:52.171215237 +0000
 +++ dbus-1.6.8/dbus/dbus-sysdeps-unix.c	2013-02-28 13:13:52.224615146 +0000
-@@ -21,6 +21,10 @@
-  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
-  *
-  */
+@@ -26,6 +26,11 @@
+ 
+ #include <config.h>
+ 
 +#ifndef HAVE_GETGROUPLIST
 +#include "getgrouplist.c"
 +#define HAVE_GETGROUPLIST
 +#endif
- 
- #include <config.h>
- 
++
+ #include "dbus-internals.h"
+ #include "dbus-sysdeps.h"
+ #include "dbus-sysdeps-unix.h"

pkgs/by-name/db/dbus/package.nix

@@ -100,6 +100,7 @@ stdenv.mkDerivation (finalAttrs: {
     "-Dinstall_sysconfdir=${placeholder "out"}/etc"
     "-Ddoxygen_docs=disabled"
     "-Dducktype_docs=disabled"
+    "-Dlaunchd_agent_dir=${placeholder "out"}/Library/LaunchAgents"
     "-Dqt_help=disabled"
     "-Drelocation=disabled" # Conflicts with multiple outputs
     "-Dmodular_tests=disabled" # Requires glib
@@ -108,10 +109,22 @@ stdenv.mkDerivation (finalAttrs: {
     "-Dsystemd_user_unitdir=${placeholder "out"}/etc/systemd/user"
     (lib.mesonEnable "x11_autolaunch" x11Support)
     (lib.mesonEnable "apparmor" stdenv.hostPlatform.isLinux)
+    (lib.mesonEnable "epoll" stdenv.hostPlatform.isLinux)
+    (lib.mesonEnable "inotify" stdenv.hostPlatform.isLinux)
     (lib.mesonEnable "libaudit" stdenv.hostPlatform.isLinux)
     (lib.mesonEnable "kqueue" (stdenv.hostPlatform.isDarwin || stdenv.hostPlatform.isBSD))
     (lib.mesonEnable "launchd" stdenv.hostPlatform.isDarwin)
+    (lib.mesonEnable "systemd" enableSystemd)
     "-Dselinux=disabled"
+  ]
+  ++ lib.optionals stdenv.hostPlatform.isDarwin [
+    # `launchctl` is only needed at runtime. Lie to `find_program` because it will always be present on a Darwin host.
+    "--cross-file=${writeText "darwin.ini" ''
+      [binaries]
+      launchctl = 'true'
+    ''}"
+  ]
+  ++ lib.optionals enableSystemd [
     "--cross-file=${writeText "crossfile.ini" ''
       [binaries]
       systemctl = '${systemdMinimal}/bin/systemctl'