This seems like a problem that's really hard to google! Which is why I finally came here after so long. I was compiling the updated Half-Life SDK, and I get approx. 4000 lines of errors, all within default headers/
I tried reinstalling g++-multilib, being the primary dependency listed, but evidently it didn't help. I also tried any gcc packages I thought of, none of which worked.
Compiling under latest Ubuntu stable.