Building fails when cross compiling a static build

When crosscompiling qtbase statically with the -prefix and -hostprefix option and then compiling qtdeclarative for that the build fails, because some library paths are not correctly prefixed with the sysroot (e.g. -L/usr/local/qt/plugins/bearer is used instead of -L$SYSROOT/usr/local/qt/plugins/bearer).

A workaround for this problem is using -extprefix instead of -hostprefix and making -extprefix identical to -prefix (not sure this is necessary), but it would be nice if this can be fixed.