RFE: option to avoid autoreconf recursion

[Bruno Haible]

Hi,

For gnulib-tool, it would be useful if 'autoreconf' had an option
  --no-recurse or --no-recursion or --no-recursive
that would avoid recursive self-invocations of autoreconf.

The use case is: gnulib-tool creates many directories with each a
Makefile.am and configure.ac and configure file, and on top of that
an extra Makefile.am and configure.ac and configure file. When the
subdirectories are created, autoreconf is already executed on such a
subdirectory. Therefore recursion is not needed.

Currently, on a slow machine, "gnulib-tool --create-megatestdir" takes
ca. 4 hours of CPU time when using aclocal/autoconf/automake for the top
level, and ca. 7-8 hours when using autoreconf. autoreconf is just redoing
useless recomputations.

Bruno