circleci: actually build in 32-bit mode
circleci: actually build in 32-bit mode

Before this the compilers were installed, but I didn't change CC/CXX
from gcc/gc++ to x86_64-linux-gnu-gcc/x86_64-linux-gnu-g++.  Oops.

nemequ/simde,nemequ/simde,nemequ/simde