Require GNU make to build binutils-gdb

[Simon Marchi]

On 2016-11-17 15:06, Mike Frysinger wrote:
>> In the eventuality this proposition is accepted, should we have a 
>> check
>> in the top-level Makefile that warns the user early if their version 
>> of
>> make is not supported?
> 
> seems like it should be adopted by gcc first ?

I am not sure how the management of the top-level files work, so I'll 
let others respond.

But as Andreas Schwab mentioned in our earlier discussions, there is 
already such a check for gcc:

   @if gcc
   ifeq (,$(.VARIABLES)) # The variable .VARIABLES, new with 3.80, is 
never empty.
   $(error GNU make version 3.80 or newer is required.)
   endif
   @endif gcc

Since we don't have a particular reason to want 3.81 over 3.80, we could 
just re-use this check (make it unconditional), if that makes it easier.

> for sim/, i have no problem having it follow gdb, although i was 
> planning
> on converting it to automake ...

I think that's a good thing then, automake probably plays better with 
GNU make than other makes.