Use updated version of qemu that emulates vmsumudm properly on ppc

.gitlab-ci.yml

@@ -144,8 +144,8 @@ Debian.cross.x86:
   - apt-get update -q
   # remove any previously installed nettle headers to avoid conflicts
   - for arch in armhf arm64 ppc64el;do apt-get remove -y nettle-dev:$arch;done
-  - if [ "$host" == "powerpc64-linux-gnu" ];then apt-get update && apt-get install -y gcc-$host g++-$host && export QEMU_LD_PREFIX=/usr/$host EXTRA_CONFIGURE_FLAGS='--enable-mini-gmp';fi
-  - if [ "$host" == "powerpc64le-linux-gnu" ];then apt-get update && apt-get install -y gcc-$host g++-$host libgmp-dev:ppc64el && export QEMU_LD_PREFIX=/usr/$host;fi
+  - if [ "$host" == "powerpc64-linux-gnu" ];then apt-get install -y software-properties-common && add-apt-repository "deb http://deb.debian.org/debian bullseye-backports main" && apt-get update && apt-get install -y -t bullseye-backports binfmt-support qemu-user && apt-get install -y gcc-$host g++-$host && export QEMU_LD_PREFIX=/usr/$host EXTRA_CONFIGURE_FLAGS='--enable-mini-gmp';fi
+  - if [ "$host" == "powerpc64le-linux-gnu" ];then apt-get install -y software-properties-common && add-apt-repository "deb http://deb.debian.org/debian bullseye-backports main" && apt-get update && apt-get install -y -t bullseye-backports binfmt-support qemu-user && apt-get install -y gcc-$host g++-$host libgmp-dev:ppc64el && export QEMU_LD_PREFIX=/usr/$host;fi
   - if [ "$host" == "s390x-linux-gnu" ];then apt-get update && apt-get install -y gcc-$host g++-$host libgmp-dev:s390x && export EXTRA_CONFIGURE_FLAGS='--disable-assembler';fi
   script:
   - build=$(dpkg-architecture -qDEB_HOST_GNU_TYPE)