debugging feature for recursive rules

[Karl Berry]

I have found myself needing to go through the complicated shell
sequence for the $(RECURSIVE_TARGETS) rule more than once when debugging
the Makefile.am's in a big directory tree (namely TeX Live).  Typically
I get a mysterious "*** failed", exit status 1, and there's no easy way
to know which command failed.

I'd like to suggest that that initial silencing "@" become a variable,
say RECURSIVE_TARGET_VERBOSE.  Of course the default would still be @,
but then it could easily be overridden with, say, "set -vx;", to at least help
narrow down the point of failure.

Wdyt?

Thanks,
Karl