[PATCH] Kill __errno_location PLT slot in --with-tls --with-__thread build

[Roland McGrath]

In your changes, on ia64 now there will be no ldexp{,f,l} in libm at all.
Was that the plan?  I think that will break versioned dependencies.

I did some pure makefile hackery to generate the m_foo.? source files (two
more rules per dir in sysd-rules) that dtrt for .c vs .S generically.  It
needs nothing in sysdeps, and won't require any more files anywhere if we
need to do the same for another of those modules.