message: build: add linker optimization flags to guix
  Any -O argument will enable optimizations in GNU ld. We can use -O2
  here, as this matches our compile flags. Note that this would also
  enable additional optimizations if using the lld or gold linkers,
  when compared to -O0.
diff: @@ -177,7 +177,7 @@ HOST_CXXFLAGS="$HOST_CFLAGS"
  # LDFLAGS
  case "$HOST" in
  - *linux*) HOST_LDFLAGS="-Wl,--as-needed -Wl,--dynamic-linker=$glibc_dynamic_linker -static-libstdc++" ;;
  + *linux*) HOST_LDFLAGS="-Wl,--as-needed -Wl,--dynamic-linker=$glibc_dynamic_linker -static-libstdc++ -Wl,-O2" ;;
  *mingw*) HOST_LDFLAGS="-Wl,--no-insert-timestamp" ;;
  esac
  