itstool: fix cross, fix python warnings

pkgs/by-name/it/itstool/package.nix

@@ -2,7 +2,10 @@
   stdenv,
   lib,
   fetchurl,
+  fetchpatch,
   python3,
+  autoreconfHook,
+  versionCheckHook,
 }:
 
 stdenv.mkDerivation rec {
@@ -14,18 +17,31 @@ stdenv.mkDerivation rec {
     hash = "sha256-a5p80poSu5VZj1dQ6HY87niDahogf4W3TYsydbJ+h8o=";
   };
 
+  patches = [
+    # https://github.com/itstool/itstool/pull/51
+    (fetchpatch {
+      name = "fix-insufficiently-quoted-regular-expressions-pr51";
+      url = "https://github.com/itstool/itstool/commit/19f9580f27aa261ea383b395fdef7e153f3f9e6d.patch";
+      hash = "sha256-5J4mRXQu24o2rqVtaXN/ETgj6A8R0Ym+YkZhqhZTzIc=";
+    })
+  ];
+
   strictDeps = true;
 
+  postPatch = ''
+    # Do not let autoconf find Python, but set it directly. This fixes cross-compilation.
+    substituteInPlace configure.ac \
+      --replace-fail 'AM_PATH_PYTHON([2.6])' "" \
+      --replace-fail 'AC_MSG_ERROR(Python module $py_module is needed to run this package)' ""
+    substituteInPlace itstool.in \
+      --replace-fail "@PYTHON@" "${python3.interpreter}"
+  '';
+
   nativeBuildInputs = [
-    python3
+    autoreconfHook
     python3.pkgs.wrapPython
   ];
 
-  buildInputs = [
-    python3
-    python3.pkgs.libxml2
-  ];
-
   pythonPath = [
     python3.pkgs.libxml2
   ];
@@ -34,6 +50,9 @@ stdenv.mkDerivation rec {
     wrapPythonPrograms
   '';
 
+  nativeInstallCheckInputs = [ versionCheckHook ];
+  doInstallCheck = true;
+
   meta = {
     homepage = "https://itstool.org/";
     description = "XML to PO and back again";