* cipher/dilithium.c: Add the Dilithium reference implementation into
one file.

for f in ntt.c packing.c poly.c polyvec.c reduce.c rounding.c \
         sign.c symmetric-shake.c
  do echo "/*************** dilithium/ref/$f */"
  grep -v '^#include' $f
done > /tmp/dilithium.c