Per-machine additions to CFLAGS-rtld.c being overridden.

[Joseph S. Myers]

This looks exactly like the issue I raised in 
<http://sourceware.org/ml/libc-alpha/2012-11/msg00798.html> - where I 
think no-one commented on a general rule for the ordering of contents of 
subdirectory Makefiles.

-- 
Joseph S. Myers
joseph@codesourcery.com