After some sleuthing I figured out this undesired behavior under gcc 4.8 is due to gcc's
pre-processor now pre-including stdc-predef.h for the translation unit to make it fully C11-compliant.
This quick patch
I put together, while not elegant, solves the problem. I've alerted upstream but
given blank lines should not break anything, I wouldn't count on much effort being invested in this.