When using bootchart2 with a qemu-x86_64 target (where /lib64 is standard LIBDIR instead of /lib) bootchartd fails to function. This script is hardcoded to look for /lib/bootchart/bootchartd-collector whereas the component in question is getting installed to /lib64/bootchartd/bootchartd-collector. Probably the makefile should be patched to sed the bootchartd script so that the proper LIBDIR makes it in.
Configure with qemux86-64, standard kernel, glibc-small and --with-package=bootchart2. Build target image, add "init=/sbin/bootchartd" to boot line, and note the errors from bootchartd.