[Bug ada/85007] -b flag to gnatlink not recognized

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85007

--- Comment #13 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> It looks from gnatlink.adb:540 (of 7.3.0), if the "--GCC=" flag is
> specified, it short-circuits all other args that normally would have been
> passed to the linker, including the optimization level, "-m32", "--RTS=32",
> and any other flags that were passed in the compiler section of the GPR file.

Right, historical quirk, but we're not going to change that now.