Note that I tried Debian's build of GCC, with the same issue. But, if I build the source straight from mozilla-central, then I don't have any issues (with either build of GCC).
Building our package without DEB_BUILD_HARDENING makes the problem go away. From looking at the hardening wrapper script, this narrows the problem down to -fstack-protector or -D_FORTIFY_SOURCE=2
Note that I tried Debian's build of GCC, with the same issue. But, if I build the source straight from mozilla-central, then I don't have any issues (with either build of GCC).
Building our package without DEB_BUILD_HARDENING makes the problem go away. From looking at the hardening wrapper script, this narrows the problem down to -fstack-protector or -D_FORTIFY_SOURCE=2