Building a release tarball generates trampoline files in eln-cache

[Eli Zaretskii]

Andrea,

When Emacs 28 is built from a release tarball, and the preloaded *.el
files are native-compiled with batch-native-compile, the compilation
produces trampoline files in the user's eln-cache directory.  Here's
the list of such files I have in my eln-cache, after building a
tarball on MS-Windows:

  subr--trampoline-782d6c6973742d666f6e7473_x_list_fonts_0.eln
  
subr--trampoline-782d646973706c61792d706978656c2d686569676874_x_display_pixel_height_0.eln
  
subr--trampoline-782d646973706c61792d706978656c2d7769647468_x_display_pixel_width_0.eln
  subr--trampoline-782d646973706c61792d706c616e6573_x_display_planes_0.eln
  
subr--trampoline-782d646973706c61792d636f6c6f722d63656c6c73_x_display_color_cells_0.eln
  
subr--trampoline-782d7365727665722d6d61782d726571756573742d73697a65_x_server_max_request_size_0.eln
  subr--trampoline-782d7365727665722d76656e646f72_x_server_vendor_0.eln
  subr--trampoline-782d646973706c61792d73637265656e73_x_display_screens_0.eln
  subr--trampoline-782d7365727665722d76657273696f6e_x_server_version_0.eln
  
subr--trampoline-782d646973706c61792d6261636b696e672d73746f7265_x_display_backing_store_0.eln
  
subr--trampoline-782d646973706c61792d6d6d2d686569676874_x_display_mm_height_0.eln
  subr--trampoline-782d646973706c61792d6d6d2d7769647468_x_display_mm_width_0.eln
  
subr--trampoline-782d646973706c61792d76697375616c2d636c617373_x_display_visual_class_0.eln

Is this expected, and if so, why aren't these trampoline files put
under native-lisp/ directory in the build tree?  I presume that these
trampoline files need to be installed together with the rest of *.eln,
or else the installed Emacs will not work, right?