Possible lookup cache optimization

[Jakub Jelinek]

Hi!

What about merging elf_machine_lookup_no*_p into one function which would
return a bitmask? As far as I can see they are always used together, and
having them in one char or int would mean we could pass around just one
argument, not 2, and compare one argument, not 2 when checking cache (and
also store just one).
What do you think?

Also, the prelink patch needs to be able to disable the lookup cache, so I
was thinking about using something like:
union { struct { char noexecplt; char disable; } u; int val; } noexecplt;
so that when storing, it could store into
l->l_lookup_cache.noexecplt.u.noexecplt
and when reading l->lookup_cache.noexecplt.val.
This way setting disable to nonzero would make this for free.

	Jakub