This is definitely not going to make it into glibc-2.20, so you might want to wait until we're out of release freeze to worry too much about the glibc-oriented bits. Meanwhile, you can iron out your other cleanups with gnulib folks.
For glibc you need to do some more work to make the provision of compatibility symbols clean. The entire compatibility build needs to be protected with a SHLIB_COMPAT test. The compatibility symbols need to be made unavailable at link time, using versioned_symbol macros.
