upstream glibc has dropped support for older Linux kernels.  your choices:
 - upgrade your kernel
 - switch to a different C library
 - stick with glibc-2.19 for a while

be warned though there are no plans atm to backport things to glibc-2.19.  
this includes security fixes, but more importantly as time moves on, making 
newer gcc versions sanely compile glibc.  we've kept older glibc versions 
around to be nice, and on a part time basis for cross-compiling, but none of 
those are given priority.  i.e. fixes come as people feel like doing them.

certainly once glibc-2.20+ goes stable, there is no expectation let alone 
requirement that packages in the tree be kept working with older glibc 
versions.  the maintenance cost there is unreasonable.

i guess if you're stuck on old crap, now would be a good time to start 
preparing to unstick your crap.  glibc-2.20 will most likely be in ~arch in 
the next 6 months.
-mike