I should mention that I've also installed gcc 4.9.1 to try combining
ASAN and UBSAN i.e. -fsanitize=undefined,address. So it's possible that
something in that install has upgraded a shared object somewhere else.
In the command above I'm using just "gcc" in CC, though, not "gcc-4.9".
The earlier snipped output confirms it is using gcc 4.8.2.
Anyway, posting here to see if it's just me or if there's really a minor
issue with Rdevel currently.