[adding m4-discuss]
According to Ralf Wildenhues on 7/11/2008 5:05 PM:
| I personally think it's a shame to add known-suboptimal interfaces
| like m4_prepend at all, but oh well. (I think in a better world,
| a programming language would teach users to use good algorithms by
| only providing those interfaces...)
Maybe the compromise would be provide it in m4sugar.m4, but remove mention
of it in NEWS and autoconf.texi, leaving bison to use it as an
undocumented macro. At any rate, updating bison to newer m4sugar requires
this interface, unless we rewrite bison to not need prepending.