Something is wrong with how we build libasan in our gcc. It seems to be built against the host system glibc, rather than the glibc in cenbuild. The current version of libasan.so requires glibc 2.23, but we have glibc 2.12: > /usr/lib/gcc/x86_64-unknown-linux-gnu/5.5.0/../../../../lib64/libasan.so: undefined reference to `__signgam@GLIBC_2.23'