telegram-desktop: "fix cross" for arm*-musl

Still needs proper investigation at why this is only breaking on
arm*-musl, and in general some cleanup of qt6 cmake cross

srcpkgs/telegram-desktop/patches/cross.patch

@@ -9,3 +9,11 @@
      BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR>
      COMMAND ${CMAKE_COMMAND} --install <BINARY_DIR>
      STEP_TARGETS build
+@@ -83,6 +82,7 @@
+         -DCMAKE_PREFIX_PATH=${CMAKE_CURRENT_BINARY_DIR}
+         -DECM_DIR=${extra_cmake_modules_binary_dir}/share/ECM/cmake
+         -DPlasmaWaylandProtocols_DIR=${plasma_wayland_protocols_binary_dir}/lib/cmake/PlasmaWaylandProtocols
++	-D_qtpaths_executable=/usr/lib/qt6/bin/qtpaths
+     STEP_TARGETS build
+     EXCLUDE_FROM_ALL TRUE
+     BUILD_BYPRODUCTS <BINARY_DIR>/lib/libKF5WaylandClient.a