Remove old gtk library linking.

Telegram/CMakeLists.txt

@@ -1229,18 +1229,6 @@ elseif (APPLE)
             )
         endif()
     endif()
-elseif (LINUX)
-    if (NOT TDESKTOP_DISABLE_GTK_INTEGRATION)
-        find_package(PkgConfig REQUIRED)
-
-        pkg_search_module(GTK REQUIRED gtk+-2.0 gtk+-3.0)
-        target_include_directories(Telegram PRIVATE ${GTK_INCLUDE_DIRS})
-
-        if (DESKTOP_APP_USE_PACKAGED)
-            find_library(X11_LIBRARY X11)
-            target_link_libraries(Telegram PRIVATE ${X11_LIBRARY})
-        endif()
-    endif()
 endif()
 
 if (build_macstore)