bug#47325: newlib-nano: are lib names wrong?

[Nicolò Balzarotti]

Hi guix!

A program I'm packaging requires newlib-nano, but when building, the
linker fails to find g_nano and c_nano.

I found out those names are taken from the nano.specs file we install
> cat $(guix build newlib-nano)/arm-none-eabi/lib/nano.specs | grep -- -l

-lc_nano
%{specs=rdimon.specs:-lrdimon_nano} %{specs=nosys.specs:-lnosys}
%(nano_link) %:replace-outfile(-lc -lc_nano) %:replace-outfile(-lg -lg_nano)
%:replace-outfile(-lrdimon -lrdimon_nano) %:replace-outfile(-lstdc++ 
-lstdc++_nano)
%:replace-outfile(-lsupc++ -lsupc++_nano)
%{!shared:%{g*:-lg_nano} %{!p:%{!pg:-lc_nano}}%{p:-lc_p}%{pg:-lc_p}}

However, those files are missing:
> ls $(guix build newlib-nano)/arm-none-eabi/lib/ | grep lib

libc.a
libg.a
libgloss-linux.a
libm.a
libnosys.a
librdimon.a
librdimon-v2m.a
librdpmon.a

I was able to build the program by modifing the .specs file with:

(add-after 'install 'remove-suffix
           (lambda* (#:key outputs #:allow-other-keys)
             (substitute*
                 (string-append
                  (assoc-ref outputs "out")
                  "/arm-none-eabi/lib/nano.specs")
               (("_nano") ""))
             #t))

But reading online, it seems the _nano is a common suffix.  Should we
rename the output libs?  Should we symlink?  I know nothing about this,
but it might be a bug.

Thanks! Nicolò