[PATCH] elf: Don't set version info on unversioned symbols

[Fangrui Song]

On 2021-09-18, H.J. Lu via Binutils wrote:
>Don't set version info on unversioned symbols when seeing a hidden
>versioned symbol after an unversioned definition and the default
>versioned symbol.
>
>bfd/
>
>	PR ld/28348
>	* elflink.c (elf_link_add_object_symbols): Don't set version info
>	on unversioned symbols.
>
>ld/
>
>	PR ld/28348
>	* testsuite/ld-elf/pr28348.rd: New file.
>	* testsuite/ld-elf/pr28348.t: Likewise.
>	* testsuite/ld-elf/pr28348a.c: Likewise.
>	* testsuite/ld-elf/pr28348b.c: Likewise.
>	* testsuite/ld-elf/pr28348c.c: Likewise.
>	* testsuite/ld-elf/shared.exp: Run PR ld/28348 test.

I don't find <corrupt> in readelf --dyn-syms output by linking pr28348c.o libpr28348a.so libpr28348b.so with old ld. 
Does the test case reflect the bug?

BTW, does libpr28348a.so intend to use a version script?