Boost 1.58 does not build for MIPS32 on a x86_64 machine. It worked fine for boost 1.57.

The error message is "mips-openwrt-linux-gcc: error: unrecognized command line option '-m32'"

Setting the 32-bit option in <pkg_build_dir>/bin.v2/project-cache.jam to false solves the compiler error. Didn't test the resulting package yet.