relocs against defined symbols are replaced by relative
relocs, when a GOT slot is created.  But code relocs (usually
calls via PLT) use the plt_offset member of attr, not the got_offset
member, so the "huh" warning was triggered in the case of calls to
static functions (the code still worked).

So, for now just use the AUTO_GOT_PLT mechanism.  We could also
emit a non-PLT reloc in the backend for calls to VT_STATIC functions
(like the x86-64 backend does) and do the same as for x86-64 in
build_got_entries (which transforms PLT32 into PC32 relocs, riscv
would transform CALL_PLT into CALL relocs).  Maybe later.