RFC: new RTEMS IRQ requirements

[Valette Eric]

Joel Sherrill wrote:

> Speaking strictly from a historical perspective.  RTEMS used to make 
> more use of m4 and it was a portability pain in the (*&^%#.  THe
> situation may be better now but I somehow doubt it.  

Sure, we should require gnu m4 to be installed not  system provided m4. 
If memory serves I think ralph already pointed out that gm4 should be 
present for autoconf, automake anyway...

> I recall that the original i386 port did use m4 to generate this code
> but I can't find it in CVS since CVS ONLY goes back to 1995. :)

ChorusOs irq handling was just as set a logical set of macros called in 
the right order. High level, functionnal assembler :-)

-- eric