any reason not to enforce the build requirement: m4 >= 1.4.4 ?

[Jim Meyering]

I spent some time recently tracking down a bug that arose from an autoconf
installation built using m4-1.4.2.  My testing showed that autoconf built
using any version of m4 older than 1.4.4 would have the same problem.

I'm sure it would save others from spending the time to track down this
sort of problem, if there were a configure-time or build-time check for a
working version of m4.  However, when I last checked (a week or two ago)
there was none.

I can't be the first to suggest this.
Is there some reason not to require that we're
using a working version of m4 when building?
I think I can cook up a (mis)feature test.