Fix more problems with libmng recipe (bug #47712). * src/libmng.mk: Remove unnecessary mkdir command in recipe. Call autoreconf with --force option because the libmng archive file ships with an out-of-date ltmain.sh which will not be replaced without --force.

^settings.mk
^usr/
^log/
^pkg/
^installed-packages/
^wip/
^tmp-.*/

^autom4te.cache/
^configure
^config.status
^config.log
^Makefile
^cmake-toolchain-file.stamp

^cross-tools/
^gnuplot/
^octave/
^tools/set_mxe_env.sh