my system (NetBSD 1.6) stumbled upon the configure's ACCEPT_INFERIOR_RM_PROGRAM check.
I'm guess that in the five years since you sent this report (sorry for the ridiculously delayed reply), you've probably been forced to change your system. (I use old systems too, but haven't been able to get away with quite that old. :) In any case, it's supposed to be possible to still allow "rm -f" to pass by setting the envvar ACCEPT_INFERIOR_RM_PROGRAM to "yes", and rerun configure. (E.g., message shown at bugs.gnu.org/42529.) So, closing this for automake ... --thanks for the report, karl.