tevent: copy cross fix from talloc & add libxcrypt

testing pyembed configuration : Could not build a python embedded interpreter

tevent-aarch64-unknown-linux-gnu> In file included from ../../pytevent.c:26:
tevent-aarch64-unknown-linux-gnu> ../../lib/replace/replace.h:885:10: fatal error: crypt.h: No such file or directory
tevent-aarch64-unknown-linux-gnu>   885 | #include <crypt.h>
tevent-aarch64-unknown-linux-gnu>       |          ^~~~~~~~~
tevent-aarch64-unknown-linux-gnu> compilation terminated.

1 files changed, 7 insertions, 0 deletions

diff --git a/pkgs/development/libraries/tevent/default.nix b/pkgs/development/libraries/tevent/default.nix
index f10235650c4a3..7b798d00b01e1 100644
--- a/pkgs/development/libraries/tevent/default.nix
+++ b/pkgs/development/libraries/tevent/default.nix
@@ -10,6 +10,7 @@
 , docbook_xml_dtd_42
 , which
 , wafHook
+, libxcrypt
 }:
 
 stdenv.mkDerivation rec {
@@ -36,6 +37,7 @@ stdenv.mkDerivation rec {
     cmocka
     readline # required to build python
     talloc
+    libxcrypt
   ];
 
   # otherwise the configure script fails with
@@ -52,6 +54,11 @@ stdenv.mkDerivation rec {
     "--builtin-libraries=replace"
   ];
 
+  # python-config from build Python gives incorrect values when cross-compiling.
+  # If python-config is not found, the build falls back to using the sysconfig
+  # module, which works correctly in all cases.
+  PYTHON_CONFIG = "/invalid";
+
   meta = with lib; {
     description = "An event system based on the talloc memory management library";
     homepage = "https://tevent.samba.org/";