calibre: Fix build with CA derivations (#124227)

See https://github.com/NixOS/nix/issues/4764

pkgs/applications/misc/calibre/default.nix

@@ -40,10 +40,8 @@ mkDerivation rec {
   ]
   ++ lib.optional (!unrarSupport) ./dont_build_unrar_plugin.patch;
 
-  escaped_pyqt5_dir = builtins.replaceStrings ["/"] ["\\/"] (toString python3Packages.pyqt5);
-
   prePatch = ''
-    sed -i "s/\[tool.sip.project\]/[tool.sip.project]\nsip-include-dirs = [\"${escaped_pyqt5_dir}\/share\/sip\/PyQt5\"]/g" \
+    sed -i "s@\[tool.sip.project\]@[tool.sip.project]\nsip-include-dirs = [\"${python3Packages.pyqt5}/share/sip/PyQt5\"]@g" \
       setup/build.py
     sed -i "s/\[tool.sip.bindings.pictureflow\]/[tool.sip.bindings.pictureflow]\ntags = [\"${python3Packages.sip.platform_tag}\"]/g" \
       setup/build.py