Require GNU make to build binutils-gdb

[Nick Clifton]

Hi Simon,

>> I think that this is a good idea, although maybe it would be
>> helpful to take a two stage approach: for one release (of
>> binutils) issue an error message if a non-GNU make is used,
>> but allow a configure option to override this.  (In the same
>> way that obsolete targets are currently handled).  Then for
>> the release after that make GNU make a hard requirement.

> That seems fair.  Would you add that check in the top-level 
> Makefile or in the binutils/ Makefile?

Well, the top-level Makefile is shared with gcc, so we would have
to get approval there as well.  Putting the check in the binutils/
Makefile would certainly be easier, and it should be sufficient
(The only target that I could find that does not build the binutils
sub-directory is the v810, which is not supported as a binutils
target anyway).

Cheers
  Nick