xregs_via_sig: Add a work around for aarch64

[dchagin]

Summary

Due to lazy binding rtld can trash q16-q31 as they are caller saved.
Call my_pause() early in main to ensure any needed symbols has been
resolved.

[kib]

Hm wouldn't it better to fix the issue instead?
Is it enough to build rtld with the right compiler options?

I suspect we might need to stop reusing str*.o from libc, building all object files anew for rtld.

[dchagin]

In D40385#919415, @kib wrote:

Hm wouldn't it better to fix the issue instead?

+1

Is it enough to build rtld with the right compiler options?

I know only -mgeneral-regs-only, however it is not enough

I suspect we might need to stop reusing str*.o from libc, building all object files anew for rtld.

Could you please point me, I can't find it

[kib]

Look at libexec/rtld-eld/rtld-libc/Makefile.inc