Exporting linker options from library GPR

[Simon Wright <simon@pushface.org>]

I'm working with SDLAda, thanks Luke, on macOS, using a prebuilt SDL2,
which comes as a framework.

Whenever another project needs to link against the library project
concerned, it has to use the options

   ("-F", external ("HOME") & "/Library/Frameworks",
    "-framework", "SDL2")

I tried (in this project)

   Linking_Options := ("-F", external ("HOME") & "/Library/Frameworks",
                       "-framework", "SDL2");
   for Library_Options use Linking_Options;
   package Linker is
      for Default_Switches ("ada") use Linking_Options;
   end Linker;

(which results in the warning that Linker switches aren't taken account
in library Projects)

and in the using project

   package Linker renames SDLAda.Linker;

I could avoid the warning by omitting SDLAda.Linker and writing in the
using project

   package Linker is
      for Default_Switches ("ada") use SDLAda.Linking_Options;
   end Linker;

These workrounds are all very well, but is there any way of telling the
final linker to add these switches automatically?