`automake' can generate a Makefile.in that does not fit `configure' if the
version of Autoconf it uses to trace `configure.ac' differs from the version
used to generate `configure'.
Suppose you'll unpack and configure a software distribution bootstrapped with
Autoconf 2.60 and Automake 1.9.6. You have Autoconf 2.59 and Automake 1.9.6
installed. You edit some `Makefile.am', and the Automake-supplied rule calls
`automake' and `config.status' to regenerate `Makefile.in' and then `Makefile'.
The Autoconf 2.59 used to trace `configure.ac' will not recognize `datarootdir'
as a substituted variable, so `Makefile.in' will have no `datarootdir =
@datarootdir@'. `configure', generated by a newer Autoconf, will substitute
`datadir = ${datarootdir}', yielding an empty `$(datadir)' in makefiles.
Is there something reasonable that we can do to prevent or diagnose this
situation? Something like [1] is an option, though not too pleasing.
[1] http://lists.gnu.org/archive/html/bug-autoconf/2005-03/msg00027.html
