bug#32269: Expanding variables

[Philip Prindeville]

> On Jul 25, 2018, at 4:15 PM, Eric Blake <address@hidden> wrote:
> 
> On 07/25/2018 05:06 PM, Philip Prindeville wrote:
> 
>> Well, the above assumes Gnu Make, yes.
>> How many other flavors of Make does automake/autoconf work with?
> 
> At the moment, all of them.
> 
> Automake 2.0 (currently a work in progress if you check out the right 
> branches in git) requires GNU make, for more compact makefiles at the expense 
> of ditching portability to other arcane makes, now that GNU make is more 
> likely to be easily obtained on modern systems.  But automake 1.x still tries 
> as hard as possible to produce Makefiles portable to all common make 
> implementations, as long as your Makefile.am doesn't add non-portable code to 
> be passed through to Makefile.
> 


In the absence of Gnu make, the other choice would be to emit:

cat <<_EOF_ > /tmp/extvar$$.mk
include $(pwd)/Makefile

xyzzy:
        @echo ‘\$(variable)’
_EOF_

then we could run “variable=$(make -f /tmp/extvar$$.mk xyzzy)” from inside 
configure… a little uglier than using val.% as a target, but…