[PATCH v6 3/5] Add GLIBC_ABI_DT_RELR for DT_RELR support

[Fangrui Song]

On 2022-03-30, Adhemerval Zanella via Libc-alpha wrote:
>
>
>On 30/03/2022 16:22, Joseph Myers wrote:
>> On Wed, 30 Mar 2022, Adhemerval Zanella via Libc-alpha wrote:
>>
>>> But it still does not fail when the architecture does not actually implement
>>> RELR even when static linker does:
>>
>> The dynamic linker is supposed to support executing binaries using RELR
>> relocations on all architectures - there's not meant to be anything
>> architecture-specific about that support.  What's architecture-specific is
>> the static linker support (thus, if missing in the static linker used to
>> build and test glibc, then (a) the dynamic linker could still run binaries
>> using RELR if they were built using some other static linker, but (b) none
>> of the glibc binaries, either installed or test, will contain any RELR
>> relocations themselves).
>>
>
>Indeed, I was confused by the expected support.  This part seems ok H.J.

Agree. Having the generic support helps GNU ld developers to contribute
RELR for non-x86. 
When I first seen "Add --disable-default-dt-relr" I was thinking whether
it is necessary to add this so early, but then I realized that this
essentially turns the whole glibc testsuite into tests
for GNU ld's RELR support. binutils itself has very few run-time tests
and bugs tend to be difficult to surface.