libwebsockets: Fix CMake config for static build (#507822)

pkgs/by-name/li/libwebsockets/package.nix

@@ -69,6 +69,13 @@ stdenv.mkDerivation (finalAttrs: {
       ]
   );
 
+  # Remove after https://github.com/warmcat/libwebsockets/pull/3567 has been merged or otherwise addressed
+  postPatch = lib.optionalString stdenv.hostPlatform.isStatic ''
+    substituteInPlace "cmake/libwebsockets-config.cmake.in" --replace-fail \
+      "set(LIBWEBSOCKETS_LIBRARIES websockets websockets_shared)" \
+      "set(LIBWEBSOCKETS_LIBRARIES websockets)"
+  '';
+
   postInstall = ''
     # Fix path that will be incorrect on move to "dev" output.
     substituteInPlace "$out/lib/cmake/libwebsockets/LibwebsocketsTargets-release.cmake" \