Unbundle lua-bit (LuaBitOp) and lua-argparse: use dev-lua's.
From ::gentoo's rspamd-3.14.1-unbundle-lua.patch, refreshed for 4.2.3.

diff --git a/cmake/AddDependencySubdirectories.cmake b/cmake/AddDependencySubdirectories.cmake
index 215024c..d39ac37 100644
--- a/cmake/AddDependencySubdirectories.cmake
+++ b/cmake/AddDependencySubdirectories.cmake
@@ -68,11 +68,6 @@ function(AddDependencySubdirectories)
         find_package(doctest)
     endif ()
 
-    # Lua-specific dependencies
-    if (NOT WITH_LUAJIT)
-        add_subdirectory(contrib/lua-bit)
-    endif ()
-
     # Lua REPL support
     add_subdirectory(contrib/replxx)
     list(APPEND RSPAMD_REQUIRED_LIBRARIES rspamd-replxx)
diff --git a/cmake/InstallRspamdFiles.cmake b/cmake/InstallRspamdFiles.cmake
index 11f7169..c40b912 100644
--- a/cmake/InstallRspamdFiles.cmake
+++ b/cmake/InstallRspamdFiles.cmake
@@ -73,7 +73,6 @@ function(InstallRspamdFiles)
 
     # Install third-party Lua libraries
     install(FILES "contrib/lua-fun/fun.lua" DESTINATION ${LUALIBDIR})
-    install(FILES "contrib/lua-argparse/argparse.lua" DESTINATION ${LUALIBDIR})
     install(FILES "contrib/lua-lupa/lupa.lua" DESTINATION ${LUALIBDIR})
     install(FILES "contrib/lua-lpeg/lpegre.lua" DESTINATION ${LUALIBDIR})
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 805aa91..aaf94c6 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -232,11 +232,6 @@ if (ENABLE_CLANG_PLUGIN)
     add_dependencies(rspamd-server rspamd-clang)
 endif ()
 
-# Handle Lua JIT/Lua dependency
-if (NOT WITH_LUAJIT)
-    target_link_libraries(rspamd-server PRIVATE rspamd-bit)
-endif ()
-
 # Link additional optional dependencies
 if (ENABLE_SNOWBALL)
     target_link_libraries(rspamd-server PRIVATE stemmer)
diff --git a/src/lua/lua_common.c b/src/lua/lua_common.c
index 202420a..b946c20 100644
--- a/src/lua/lua_common.c
+++ b/src/lua/lua_common.c
@@ -916,10 +916,6 @@ rspamd_lua_wipe_realloc(void *ud,
 	return NULL;
 }
 
-#ifndef WITH_LUAJIT
-extern int luaopen_bit(lua_State *L);
-#endif
-
 static unsigned int lua_initialized = 0;
 
 lua_State *
@@ -1001,7 +997,6 @@ rspamd_lua_init(bool wipe_mem)
 	luaopen_svg(L);
 	luaopen_caseless_table(L);
 #ifndef WITH_LUAJIT
-	rspamd_lua_add_preload(L, "bit", luaopen_bit);
 	lua_settop(L, 0);
 #endif