Request to drop daft GNU extension

[David Edelsohn]

	It's use may be unnecessary, but getting all of the old code
corrected is difficult, especially if the code is useful yet no longer
maintained. 

	Is it possible to have this as a switch which initially accepts
the code and warns, so that in the next release after the one with the
warning we can turn it off by default yet allow people to compile the old
code if they must?

David