At Sean's request I rebuilt all of our ROOT 5.34.26 builds enabling roofit at JLab. This is now the default for ROOT 5 in build_scripts. The exception is jlabl1 (RHEL6.7, i686). There the roofit build failed. See https://markito3.wordpress.com/2015/12/15/error-building-root-on-jlabl1-with-roofit-enabled/ for details.