xorg.xdm: drop outdated patch

pkgs/servers/x11/xorg/overrides.nix

@@ -164,7 +164,6 @@ self: super:
   });
 
   xdm = super.xdm.overrideAttrs (attrs: {
-    patches = (attrs.patches or []) ++ [ ./xdm-fix-header-inclusion.patch ];
     buildInputs = attrs.buildInputs ++ [ libxcrypt ];
     configureFlags = attrs.configureFlags or [] ++ [
       "ac_cv_path_RAWCPP=${stdenv.cc.targetPrefix}cpp"

pkgs/servers/x11/xorg/xdm-fix-header-inclusion.patch

@@ -1,29 +0,0 @@
-On glibc-2.36 this fails with
-
-    genauth.c:45:12: fatal error: bsd/stdlib.h: No such file or directory
-       45 | #  include <bsd/stdlib.h>
-          |            ^~~~~~~~~~~~~~
-
-This is because the file will be included if HAVE_ARC4RANDOM is true and `__linux__` is set.
-However, this is wrong: arc4random is now defined in glibc-2.36 and thus stdlib.h must be included
-even though HAVE_ARC4RANDOM is true.
-
-diff --git a/xdm/genauth.c b/xdm/genauth.c
-index cd2ad61..74d0ae1 100644
---- a/xdm/genauth.c
-+++ b/xdm/genauth.c
-@@ -40,13 +40,7 @@ from The Open Group.
- 
- #include <errno.h>
- 
--#ifdef HAVE_ARC4RANDOM
--# ifdef __linux__
--#  include <bsd/stdlib.h>
--# else
--#  include <stdlib.h>
--# endif
--#endif
-+#include <stdlib.h>
- 
- #include <time.h>
- #define Time_t time_t