Hi Alex,
This subject is explained in "Package Transformation Options" section of the documentation. In short: --system means try to build natively for the specified architecture. It is possible on the arch that support multiple personalities (i686 and x86 for instance), or using QEMU binfmt_misc mechanism. The argument is an arch name like "x86_64-linux", "armhf-linux" or "aarch64-linux". --target means cross-compile for the specified architecture. The argument is a GNU triplet such as "mips64el-linux-gnu". Mathieu
