[RFC] Expanding the hwcap

[Roland McGrath]

AT_HWCAP2 seems adequate for the time being, as others have said.

But I don't think there's anything wrong with the extensible vDSO approach.
It doesn't need to induce any runtime overhead (beyond the startup time
cost of finding the magic in the vDSO).  struct rtld_global_ro can just
contain a fixed-sized array large enough for all the bits that libc code
actually tests.  The startup code will copy into that from the vDSO values,
rather than the code testing the bits following a pointer into the vDSO.


Thanks,
Roland